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Bob says
Here’s what I need: The circuit in this link is the basic idea (https://www.homemade-circuits.com/logic-sequence-controller/) but instead of a free running oscillator to increment or decrement the sequence, I need to be able to step through the sequence using one of 2 momentary switches – an ‘Up’ switch and a ‘Down’ switch. They would obviously need to be bounce-proofed. I would like to be at the ‘lowest’ state when powered on. Show me what needs modified or added to accomplish this.
thanks,
Bob
Swagatam says
The above design is not my design actually, and I can’t figure out how to modify this for using with a two switches, as per your requirement.
RICHARD Z. says
I have searched but was unable to locate a circuit that I could build that would display the total life run time, remaining runtime (counter reset on user input) and voltage output for a portable gas generator.
I figure I could tap into one of the output plugs to trigger a counter for life time and remaining run times as well as the available voltage.
>The ‘remaining runtime’ is a countdown timing for when the oil needs to be changed and the duration is user input.
>The ‘total life run time’ needs to be stored in memory.
>optional date/time would be nice but only is simple to implement.
Thank you.
Swagatam says
Sorry, that looks a bit complicated, I do not have this circuit with me right now.
Abhishek says
hello sir, I tried to make a drill speed controller, can you please elaborate on the bridge rectifier SCR speed controller circuit, like should allthe 3 lega of the potentiometer be connected etc. please can you redraw the circuit diagram with proper + , – symbols. thank you.
Swagatam says
Hello Abhishek, please ask this question, under the same article where the schematic is located.
Harish K says
hi sir
please note my Mobil number 9440668851
I have a requirement to make solar induction stove
Swagatam says
Hi Harish, I would recommend you to buy a readymade induction heater assembly and then connect it with a solar panel, because building an induction heater can be quite complex.
Murugesh says
to me I want rf discharge circuit and I saw online that you have it, I want it. how works. Run it in a copper box. Can it? how That is to do. to me Say it has. Radiation goes to a torch bulb 2.5 v 5amps fuse. Please tell me if you can do it. What is the rate and where is it available?
Swagatam says
I only have the circuit idea, I do not have a prototype built. I cannot build it for you.
You will have to contact a qualified engineer and get it constructed for you.
Rashid abdallah says
hello swagatam I always do electrical installation, but the challenge I have is to make a circuit that turns on all AC bulbs in the house and the circuit can sense when ac electricity gets off it will automatically turn on the DC bulbs line so I wanted you to design a circuit diagram thanks
Swagatam says
Rashid, you can try the following concept:
https://www.homemade-circuits.com/wp-content/uploads/2023/06/transformerless-DPDT-relay-control-circuit.jpg
Rashid abdallah says
swagatam I wanted you to design an automatic turn on inverter that allows AC current flow to the tv and decoder and it automatically turns on the inverter to supply AC power to the tv and decoder when AC power goes off
Swagatam says
Rashid, If you already have the inverter unit with you, you can convert it into an UPS using simple relay changeover as explained in the following article:
https://www.homemade-circuits.com/how-to-convert-inverter-to-ups/
Marc H says
Hi
What is a circuit that will variably dim a 12v DCvhalogen bulb not using the pulse method that turns it on and off for varying parts of the cycle, but changes the brightness of the bulb. (Is this accomplished by reducing the voltage?) I am doing an art project that will require different levels of brightness in different venues depending on the size, ambient light, etc. of the venue so I want to be able to set the brightness exactly each time. I need to use a halogen bulb because it is a point source of the light. It will be on for a maximum of 2 1/2 hours at any time so I could use a lead acid battery (using 10.5 amp-hours in the 2.5 hours) so it is a straight DC source. I would appreciate the advice. Thanks.
Swagatam says
Hi,
If you use the voltage control method instead of the PWM or the pulse method then the power usage won’t be efficient and your battery would deplete faster. Therefore, a PWM method is the recommended technique. The fast ON/OFf of the lamp cannot be identified due to persistence of vision.
Murugesh says
dear sir
yours conact number plesae
Swagatam says
Murugesh, you can discuss with me through comments, I will be happy to help!
Marc Hoffman says
Dear Swagatam,
I was careful to explain that I cannot use the pulse method. The rapid movement of some objects will leave a stop motion effect if I use the pulse on-off method.
I also explained that I don’t care very much if the energy use is not efficient because the light will only be on a short time–2.5 hours–and my lead-acid battery can handle it.
So I am still looking for an anwer to my question to variably dim a 50w 12v halogen bulb, as I wrote it.
Thanks.
Marc H
Swagatam says
Dear Marc,
I don’t think you explained the above things in your previous comment.
Anyway, if power efficiency is not an issue, you can try building the 1st circuit from the following article:
https://www.homemade-circuits.com/how-to-make-versatile-variable-voltage/
For further questions please ask them under the above linked article.
Ikechukwu Agbarakwe says
Good day Swargatam,
Can you advise on how to build a circuit that has a 12V SLA battery and 2 capacitors (super perhaps), as well as an oscillator? The circuit works as follows: in one cycle, the capacitors are connected in parallel, and the battery charges them up to 12V. In the next cycle, the capacitors are connected in series and discharge into the battery. All the while, a motor or power output (transformer/inverter circuit) is powered by the charge/discharge cycle. So we are recycling the power in the battery while using it to perform useful work. For reference to the circuit’s theoretical proposition, check this URL: http://www.free-energy-info.tuks.nl/Chapt5.html. In the page, search for the term: Bozidar Lisac’s Power-Boosting System.
I tried creating this circuit, using a latching DPDT Relay switch and a 555 astable oscillator circuit for the switching, but I want to benefit from your great and benevolent experience.
Thanks so much for your anticipated help!
Swagatam says
Hello Ikechukwu,
I do not have any practical experience with free energy devices an concepts, so it can be difficult for me to advise on these subjects. I would recommend you to visit the free energy forums to get the answers from the experts.
Murugesh says
need rf discharge circuit sir is available frome ur side
Swagatam says
I have a circuit but it is not tested by me. Here’s the link:
https://www.homemade-circuits.com/making-strong-rf-discharge-circuit/
Arijit says
I Want to convert 4-20ma current output coming from humidity sensor to 0-3.3v using Rail to rail opamp so I cad read it to ADC ic connected to my Raspberry Pi. Any circuit Idea ,please help me in it.
Thank You
Arijit
Swagatam says
I don’t have the exact circuit, however you can refer to the following concept and modify the designs accordingly:
https://www.homemade-circuits.com/light-meter-circuit-with-led-bar-graph/
JS8 says
Could you please explain this circuit. It’s driven by a PIR sensor. It’s supposed to function as an opened ring counter. Wouldn’t all the transistors just conduct constantly?
https://www.homemade-circuits.com/wp-content/uploads/2023/06/sequential-transistor-conduction.jpg
Swagatam says
Yes, all the transistors would remain permanently switched ON due to the presence of the base/positive resistors.
JS8 says
Thanks for the reply. I’m wanting to use a pir sensor with an h-bridge to automatically control a 12-volt motor to open then shut a valve after a desired amount of time. After the pir-rc signal I thought to use a delay then on stage to then initiate another on, delay, off to close the valve but I’m not sure how or if this could be done with basic discrete components. I’d appreciate any circuit ideas for sequential timing circuits to accommodate the mentioned task.
Swagatam says
I could not understand the following sentence:
“After the pir-rc signal I thought to use a delay then on stage to then initiate another on, delay, off to close the valve…”
Please explain in a proper way.
josh standridge says
I thought to open and close the valve I could maybe use 3 resistor, capacitor timing circuits. One being from the pir module and using its output to open a mosfet to drive the motor. Then to keep the valve open for a desired time I’d use a delay, then ON followed by another ON delay OFF circuit to close the valve. As mentioned, I’m not sure if this could work and I’m really just wanting to know if there is a way to automate a valve without IC’s.
Swagatam says
A motor is not required to open or a close a valve, a valve can be directly operated with a 12V supply to alternately open or close. The delay timing may be possible but not through an H-bridge, that looks difficult.
JS8 says
By valve I mean a water hose shut off valve and being rotational. I’m wanting to make a home-made motion detecting sprinkler. I think commercial ones do use a slide valve which is opened electrically and held closed by a spring. Is that the sort of valve you were referencing? I know I could use Arduino or such, but I’m more interested to know of a way to do this without software. Thanks again for your correspondence.
Swagatam says
Yes, I was referring toe solenoid controlled water valve system, which won’t require a H bridge rectifier rather can be controlled using a single MOSFET or a relay. The switch OFF delay and the switch ON delay can be implemented using a transistor circuit.
Nick says
Hello and thanks for reading my comment. Swagatam! Also sorry in advance for my English because I am from Greece. I want to make a circuit with 9V input. It has a microphone and a 20Ω 200mW speaker. Also I must put 3 bjt transistors : one with common collector , one with common base and finally one with common emitter.
Swagatam says
Thank you Nick, I do not have the exact configuration you are looking for, however there are a few MIC amplifier circuits explained in the following article which you can refer to:
https://www.homemade-circuits.com/small-amplifier-circuit/
Nick says
Thank you very much!
Mahadev M says
Hello Swagatam,
I came across your website while searching for DIY projects.
I want to build an UPS for 5 KW (240AH / 300Ah x 4 batteries ) (Lithium Phospate batteries) project.
Is it possible to help in creating a circuit diagram and components required.
Below are the functionalities required.
1. Inverter
2. Battery Charging ( Auto on / Auto Cutoff )
3. Minimal switch over time from main to Inverter
4. Over load protection,
5. over voltage and over current protection
6. MCB inclusion for safety.
I really appreciate if you can help.
Battery pack will be separately created with BMS
Thanks in advance.
Swagatam says
Hello Mahadev,
A 5 KW inverter will need to be built using ferrite core transformer, which can be very complex. The first step would be to build this circuit successfully, the rest of the things can be then built and integrated step-wise with the inverter without much difficulty. You can check out the following circuit and see whether or not it is feasible for you to build:
https://www.homemade-circuits.com/5kva-ferrite-core-inverter-circuit/
Dhirendra Saraswat says
Please provide me a circuit for efficient 3W led flashlight, with a fuse protection using alkaline batteries cell 1.5 V two cells or 3 cells whichever gives best efficiency for batteries. The inside temp of Flashlight should also not get high.
Swagatam says
If your LED is a standard 3.3 V type then you can directly connect it across the 3 V battery via a switch. Make sure to mount the LED on a appropriate heatsink.
Dhirendra says
can I use a PWM for better battery life. Any circuit advise for it please.
Swagatam says
If you use PWM, the LED illumination will decrease, depending on the PWM duty cycle.
abdul says
sir please let ask you about 2 circuit
1 simple clap switch diagram
2 simple solar street light automatic circuit
Swagatam says
Abdul, You can see the following links:
https://www.homemade-circuits.com/make-simple-electronic-clap-switch/
https://www.homemade-circuits.com/3-simple-automatic-street-light-circuits-explored/
Rashid abdallah says
hello sir I thank you for your knowledge that you have helped alot of people, but please sir I was requesting for your help to help me please because this list of things have always been troubling me:
1. how to make a dc to dc converter of 13v to 12v ?
2. how to make solar charge controller of 100 watts or a solar charge controller that can handle 2 solar panels for which each solar panel shall be 100w , so if we combine 100w + 100w it will be 200w , please help me sir
Swagatam says
Thank you Rashid,
1) You can reduce 13 V to 12 V by simply adding two rectifier diodes in series with the positive supply line.
2) Can you please provide the load specifications or maybe the battery voltage and current specifications?
Rashid abdallah says
please swagatam make a design for the first controller of 100w panel charging 100ah battery,
and you can help design another controller that can charge 150ah battery
Swagatam says
Rashid, you can try the following circuit. Adjust the 10K preset to produce exactly 14 V for your 12 V battery:
https://www.homemade-circuits.com/wp-content/uploads/2023/05/LM317-boost-current-charger-circuit.jpg
Rashid abdallah says
thank you so much for your efforts in helping us ????
but I still want to disturb you about something, some few weeks ago I had seen in a certain website that it’s possible to make an incubator using 25w bulbs because I had seen a certain diagram incubator temperature controller using lm358 …etc.
please swagatam if it’s possible please help to design a better temperature controller for an incubator because you are the best
Swagatam says
No problem Rashid,
The LAST CIRCUIT from the following article will perhaps fulfill your requirement:
https://www.homemade-circuits.com/how-to-build-simple-electronic/
Rashid abdallah says
your knowledge is above thank you so so much and thank you again
Swagatam says
No problem Rashid, I appreciate your kind words.
Rashid abdallah says
swagatam I’m going to begin making it and it will be good if it will charge the 150ah big battery I have minus discharge at night and the types of resistors I can use to replace the 10k resistor you told me, now the other question I have is I saw an arrow pointing the middle of a resistor in some diagrams
Swagatam says
Rashid, in the following diagram, the 10K can be a 3-pin preset or a trimpot. The arrow head indicates the center pin of the preset
https://www.homemade-circuits.com/wp-content/uploads/2023/05/LM317-boost-current-charger-circuit.jpg
Preset image:
https://www.homemade-circuits.com/wp-content/uploads/2015/09/preset-2.jpg
Rashid abdallah says
hello swagatam I’m again back to you, requesting you to please design an incubator that can use solar or dc electricity
Swagatam says
Hello Rashid,
Please post this question under the following article, I will try to help:
https://www.homemade-circuits.com/how-to-build-simple-electronic/
Rashid abdallah says
how many volts can charge a 13volt 22ah battery and can I use the very circuit you gave to me
Swagatam says
The previous circuit using 2N3055 transistor is too big for a 22 Ah battery….you can use the LM317 based circuit explained in the following article. You will have to replace the LM317 with LM338 IC, the pinout configuration will be the same:
https://www.homemade-circuits.com/how-to-make-current-controlled-12-volt/
Rashid abdallah says
ok thanks, but how can we make a sun tracker for solar panels, I mean the tracker that can carry a weight of 2.3 kilograms because 100w solar panels weigh 2.3kg
Swagatam says
It is possible to make a suntracker, but it may require knowledge and skills in mechanics and electronics. You can refer to this article for more info:
https://www.homemade-circuits.com/how-to-build-dual-solar-tracker-system/
Abdus Samad says
SUBJECT : 12V EMERGENCY UPS FOR A DVR + CCTV CAMERAS
Hello Mr. Swagatam
Thanks for providing this wonderful service as I have visited your site several times to learn stuff in the past. I have a problem I wish to discuss with you and when ever your are free or sufficient time you can give me a tip or a reference so I can resolve the issue.
I have purchase for CCTV cameras for home and a used DVR. All cameras and DVR (3 Amp) are rated for 12V and 4.5 Amperes (Each Camera 375ma so (375 x 4) + 3 Amps for DVR). However during power failure the security cam stops so I though that I can put a 12V, 40Amps car starter battery at work by connecting Positive and Negative with relevant DC sides so in case of a power failure the DVR and cameras should work without any interruption.
However the Switch mode power supply unit rated at 7 Amps for DVR and Cameras is measured exactly 12V but battery charging needs more that that (14 to 15v) but then a higher voltage may cause damage to cameras and DVR as well. I wish to avoid LM317 or similar circuits to avoid due to wastage power in heat and also relays as these may spark due to heavy amps consumption. (I do not have any 220v inverter etc. and I think that it may be an overkill as a single battery if more cost effective). By using a battery I can also light up some form of LED street lights in as emergency during power failure.
By reading your articles, a simple solution was to use a battery charger (around 4 amp as 10% charging current for 40 Amp battery) to charge battery and also to power up the cameras and DVR but four heavy Duty Diodes in series to reduce voltage (i.e. 0.6v x 4 = 2.4 v) however the charger (also a DIY. solution) may not be as good as switch mode power supply that came with DVR. I want an elegant and safe solution so want suggestions from you. ( I understand soldering well and have done some projects without any problems so even some tips or some of your suggested articles may work for me. I can mix / match to get desired results).
Thanks and regards,
Swagatam says
Thank you Abdus,
Your idea looks perfect to me, and can be configured as shown in the following diagram:
https://www.homemade-circuits.com/wp-content/uploads/2023/05/DC-UPS-for-cameras.jpg
However there’s one drawback in this circuit….during absence of input power if the battery voltage drops to 11 V then the output to the camera would also drop to 9V because of the series diodes.
Abdus Samad says
Thanks. That was quick. However I cannot say that it’s perfect as it has the draw back u mentioned. Do u have any suggestion or tip as how I can overcome the problem. Moreover u have shown the SMPS as 14v but it is 12v actually. Regards
Swagatam says
You can decrease the number of diodes to two so that the camera gets a maximum of 13 V which should be easily tolerable by the cameras.
The SMPS must have an external adjustable preset control to adjust the output voltage to 14V, otherwise it won’t help. However preset adjustable SMPS are available in the market, you will have to search for it.
James Chukwuemeka says
Please sir,
I need a complete project write up for a 1kva pure sine wave inverter.
RJ says
Hi there, im trying to create a solar light that turns on at night and charges a battery during the day. Im trying to keep it as low cost as possible. I found your solar light design. https://www.homemade-circuits.com/simplest-automatic-led-solar-light/. I was able to get it working, kind of, with your second schematic. Im wanting to light 6-8x 1w 5v leds with 2 or 3x 3.7v batteries in parallel to keep the lights running at least 4-5 hours. Im using 3x 5v solar panels in parallel to charge the batteries during the day (I’m not sure if that’s enough power but I can add more panels if needed). Eventually, I want to turn it into a PCB to keep it clean and all I would need to do is solder on the solar, LEDs, and batteries.
Swagatam says
Hi, I would suggest you the following circuit instead. Adjust the R2 to produce exactly 4.1 V for the battery, and use single LEDs in parallel instead of 3 in series.
https://www.homemade-circuits.com/wp-content/uploads/2022/08/12V-high-power-garden-poch-light-circuit.jpg
RJ says
Im not trying to use a 12v battery, just the 3.7v’s I have. The project needs to be pretty compact.
Swagatam says
You can replace the 12V battery with your 3.7 V batteries. That is why the LM338 output needs to be adjusted to 4.1 V for controlling the full charge level of the battery. The LM338 is needed to provide a regulated charging supply to the Li-ion batteries. However for this circuit a 5 V solar panel might not work, you might need an 8V or 9V solar panel.
If you don’t want the LM338 circuit, you can try the following design:
https://www.homemade-circuits.com/wp-content/uploads/2023/05/solar-garden-light-circuit-diagram-with-regulated-input-supply.jpg
Adjust the Zx zener value to get precisely 4.1 V across the battery points (without any battery connected)
Dave Frey says
Hi,
I am trying to draw up a schematic for a continuity tester for connectors w/flex prints. We have a 69 Pin and a 37 Pin connector that we solder a flex print to which we have been checking each pin and flex print trace one-by-one with a VOM. So, I need to automate this to check all the connections at once. So, I am designing a device that has a mating connector for each 69 and 37 pin connector. These will be wired to one side of each bank of LED’s and the other with the power supply and resistor. For now I am wanting to use a 12v supply but this can change. I am using RED Lumex LED’s P\N SSL-LX3054SRD that are rated 1.85v with 2.5v max. Vf at 30MA. Now I also need to add a test button to check that all the LED’s function before each test. Can you help?
Swagatam says
Hi, The cathode ends of the LEDs would need a ground connection for them to illuminate. How would you arrange these ground connections through the connectors or while testing each LED?
Dave Frey says
The ground connections are connected to the connector through the flex print. Do you have a means to submit a pdf? I can show you what I have.
Swagatam says
Can you please upload it to your Google drive and send me the link here. I will try to figure it out.
David A Frey says
Never mind that idea has been shot down now. Thanks for your input!
Nilanjan says
Can we use this office call bell in hospital..
Swagatam says
Yes you can….
rosario says
Good morning engineer. I am a person who started using LED spotlights already more than 10 years. Every now and then someone breaks down. I’ve realized that in almost all cases what’s broken is the power supply. Since I have so many, I thought maybe I can reuse them by making a bar to use to light up the garage. I don’t want to use a transformer though. It’s possible? Could you please give me a schematic I can make? There are 4 LEDs for each lamp and the declared power is 4*2w. Thank you
Swagatam says
Hi Rosario, You can try the following circuit. You can reduce C1 to 105/400V or 1uF/400 capacitor for getting 50mA for your 4 LEDs which should be connected in series:
https://www.homemade-circuits.com/wp-content/uploads/2023/03/improved-transformerless-power-supply.jpg
Please note that this circuit is not isolated from mains AC therefore is extremely dangerous to touch in an uncovered and switched ON condition.
SUDARSHAN says
sir your code for playing song on dfplayer mini module with 5 buttons worked can u provide me an code for which two ultrasonic sensor used ultrasonic sensor 1 for controling volume and ultrasonic sensor 2 for play/pause and when the hand is swapped through 1-2 it should work next and when the hand is swapped through 2-1 it should work as previous
i’m trying this for my project
pls try to help sir an request to please reply as soon as possible
Swagatam says
Hi Sudarshan,
My Arduino coding skills are not good, so it will be difficult for me to solve your problem. All Arduino articles in this blog were purchased from external sources.
rosario says
many thanks for your help.
Muwonge umaru says
I want to make an inverter welding machine using tl494 or sg3525 with a 60v DC output. In my project I want to use a ferrite transformer. And i want to be adjusting and reducing the current at the out put.so iam requesting for your guidance and related circuits
Swagatam says
Sorry, I do not have the necessary information for this project.
Doug says
Hello,
I am not a circuit designer, only a Dad. I am making a couple toys for my children that require a Simple Delay Timer Circuit. I believe your design will be perfect for these projects.
However, your 12V DC power is too much for my projects. I have size and recharging issues that are stopping me from using a12V power source. Do you have a schematic of your Simple Delay Timer Circuits that uses 1.5V, 3V or 5V? Well, I don’t really need a new schematic. A new parts list with different values for each part in your 12v design is all I really need.
If you could provide a link or list for me to view would be most appreciated.
I thank you for your very informative web site and helping me and my kids.
Doug
1-725-267-4095
Swagatam says
The 12V circuits can also work with 3V supplies, so no issues with that.
Can you please tell me what kind of delay do you require? Once power is switched ON, should the load switch ON instantly and then switch OFF after some delay, or should the load switch ON after some delay and remain switched ON.
Michael says
Greetings and Salutations Swagatam!
I am currently trying to make my own power supply that will run from AC to DC and be able to supply at least 0-100 amps variably, but have not been able to locate a schematic for such a cause. I was wondering if someone could point me in the right direction or help with the design of such a board. I was thinking a rheostat would be needed for the current output as a potentiometer would not be able to support the amount of current passing through a pot, from what I have gathered. I would like to have a digital display that would read the volts / current output accurately so I can write down the test results.
The few that I have found online are ranging from 800+ dollars which is a little more then I care to spend at this point when I know I can build one for cheaper and learn a thing or two about circuits. Any help you can provide is welcomed. And as for parts and pricing, I don’t mind spending a bit to get the job done.
Swagatam says
Thank you Michael,
100 amp is a huge amount of current and a cheap linear power supply might not be suitable at this level of current, because a linear power supply may get immensely hot at lower output voltages which can be unmanageable. The only option is to build an SMPS type of power supply.
However, presently I do not have a 100 amp rated SMPS power supply with me, If I happen to get one will surely let you know.
Michael says
Thank you very much for you insight, I did see a 50 amp build SMPS that I was thinking about building. It should be enough for what I plan to accomplish. I was hoping that there was some schematic out there I could follow but I’ll have to design and make one up myself. Thanks again for the insight.
Swagatam says
Sure, no problem, I wish you all the best!
Louis says
Hallo there.
I would like to know what the light intensity range of these circuits are. Will the preset in circuit 1 for example adjust to switch on at full sun and not before?
Will it then switch off at a level (preset if possible) with less sun but not darkness needed to switch off?
It will be interesting to know the light strength limits for switching on and off.
Thanks.
Best regards.
Swagatam says
Hi,
Can you please show me the schematic which you are referring to?
Jack says
Hello Swagatam,
I would like to build a ~100mA constant current regulator using an LM350. The purpose is to provide a trickle charge to a 12v vehicle battery that is sitting for long period. I have a rectified/filtered circuit that outputs 22vdc@500mA for the LM350 Vin. The current limiting resistor at the Vout is what I’m having difficulty with. I’d like to use an adjustable power resistor so I can tweak the current output, I just don’t know what value and wattage rating to purchase.
Thank you,
Jack
Swagatam says
Hello Jack,
You can try building the following circuit which should solve your roblem.
https://www.homemade-circuits.com/wp-content/uploads/2023/04/LM350-power-supply-circuit.jpg
Here RX is the current limiting resistor. All the resistors are 1/4 watt
Jack says
Thank you, I’ll comment after I get the circuit built and tested.
Jack
Jack says
Finally secured parts and finished the circuit which works great!
https://www.homemade-circuits.com/wp-content/uploads/2023/04/LM350-power-supply-circuit.jpg
I ended up making RX out of (5) paralleled 100 ohm 1/2 watt in parallel with (1) 100 ohm 1/2 watt trimpot which gave me the ability to fine tune the trickle current.
Thank you so much for your help.
Jack
Swagatam says
That’s great, Glad you could build it successfully! All the best to you!
Jack says
Hello, what minimum power rating does the 4.7k pot need to be? Can it also be a 5k pot?
Thank you,
Jack
Swagatam says
It can be any ordinary or standard pot, yes a 5K will also do.
CLAUDIO DE NARDIS says
Dear sir,
I have an old PANASONIC VHS Videorecorder with power supply broken.
I managed to find the schematic but I need your help.
I don’t have a professional oscilloscope, I have a DSO138,
and with the schematic I don’t know if I can verify the indicated test signals.
If it’s possible I can post the diagram and description of what I’ve already done and checked.
I hope you have the chance to help me. All the best
Claudio
Swagatam says
Hi Claudio,
Sorry, since I have never opened or checked a panasonic videorecorder, I know nothing about its internal functioning so it would be very difficult for me to troubleshoot your problem.
CLAUDIO DE NARDIS says
Thank you Sir, The problem is the power supply board of which I have the original electronic diagram
and therefore with your knowledge you would have no problem understanding the possible problem or right test.
As soon as I opened it, I saw that the output resistor of the rectifier bridge had burned out,
I changed it but it was still shorted, so I decided to go deeper into the activity to learn these circuits better.
If I link the schematic could you give me some suggestions?
Thanks in advance.
Claudio
Swagatam says
Hi Claudio, You can send the link but most probably I won’t be able to solve it because the power supply would be ab SMPS and all SMPS circuits have different designs an mode of working, so understanding a particular design and be a lot of work. You can send the link if possible if i will try to help.
Nick Yorke Whetstone says
I have built a hi-fi turntable, and have an electric motor running from a 12 volt battery. I bought a PWM speed controller off Ebay, but while it does control the speed, I can not get it to accurately adjust the speed to 33.3. Can the control unit be modified?
It seems that my motor only requires a couple of volts for the correct speed range. I noted that the video of the single-transistor control unit on your site only works from 3 volts upwards.
Swagatam says
I don’t think your circuit can be modified. If you want to control the speed by varying the supply voltage then that is also possible. You can try implementing the following concept:
https://www.homemade-circuits.com/wp-content/uploads/2022/04/variable-voltage-regulator-using-emitter-follower-transistor.jpg
Nick says
Thank you. That is simple enough to try.
Swagatam says
Sure, no problem…
Nick says
Can I use a TIP31C instead of the TIP31G?
Swagatam says
Yes you can…
Nick says
Thanks again.
Ilias Nikolaidis says
– How to Build a 400 Watt High Power Inverter Circuit
I want to build above article circuit.
In part list have this relay
RELAY = 24 VOLT, SPDT
If anyone know a eshop to buy it.
My home is in Greece
Vikram M says
Hi Swagatam sir
Hope you are well
I am making long range ultrasonic distance sensing project, I need 10m range with good accuracy.
Application: On motorcycle in external environment, while in motion
1. I used HC SR04 module (range 4m). It does not work beyond 4m.
Q:
Can you recommend ways to increase range of HC SR04 (https://robu.in/product/hc-sr04-ultrasonic-range-finder/) either via the circuit (maybe adding additional components or playing with hardware OR via changes to the coding)?
2. I found this long range (18m) ultrasonic sensor:
https://in.element14.com/multicomp/mcusd16a40s12ro/transceiver-40khz-16mm-metal/dp/2362677
I checked the documentation – it does not contain any details or circuit diagram. This is a standalone sensor without PCB, hence I need help.
Q:
Can you please guide me how to interface it with Arduino because it does not come with PCB or any guiding documents?
3. I am also thinking to use the HC SR 501 PIR sensor:
https://robu.in/product/pir-motion-sensor-detector-module-hc-sr501/?gclid=Cj0KCQjw8qmhBhClARIsANAtbofyBdyMKzv6J8oVp6eM1FzvGbdwCoY-5mHvvAehqCD935kLGGXzufsaAr6DEALw_wcB
Q:
Do you think a PIR sensor will work?
Swagatam says
Hi Vikram,
Unfortunately I have no idea how to increase the range of a 40kHz ultrasonic transmitter.
However I think the ultrasonic device could be replaced with something like a tweeter device and then experimented for enhancing the range.
You can try one of these circuits using tweeter and check if the range increases or not:
https://www.homemade-circuits.com/best-ultrasonic-transmitter-receiver-circuits-for-all-hobbyists/
I think PIR is much better, and has a higher and stronger range than an ultrasonic device.
abdul says
sir how to make simple digital programmable timer circuit
on/off circuit
please help me circuit diagram
Swagatam says
Abdul, You can try the following circuit
https://www.homemade-circuits.com/simple-digital-timer-circuit-with-2-digit-display/
abdul says
sir another question this programming I can I use in diesel engine on an off engine
Swagatam says
Sorry, I have no idea how a diesel engine can be switched ON/OFF. I guess it can e done with a relay switch but not sure.
abdul says
sir you can remember inthe company having diesel engine when electricity is come engine stop working after electricity is off engine start working this programming circuit I mean sir
thank you for
replay
Swagatam says
Abdul, diesel engine requires a complex start stop switch mechanism, which cannot be implemented with ordinary relay switches, because diesel engine will have a CDI also for starting.
Adele says
Hello! I have a project at school and I am not very sure how to do it. I need an embedded system to test how many on/off cycles a light bulb(preferably led) can perform before it breaks down. I also need to use a solid state relay preferably with zero detection powered from 230VAC and wirelessy controllable. The system contains sensors and some common socket. I am not sure how to connect The components. Could you help me? Thank you in advance.
Swagatam says
Sorry, I am not good with embedded systems so it will be difficult for me to help you with this subject.
Jose Zuria says
Hi Swagatam:
My name is Jose and I live here in the Miami, Fl area in the United States.
I have been seeing several of your projects on your page and I find them very interesting and excellently well explained. Congratulations
I am writing to you since I assemble (manufacture) some small machines to sharpen scissors for beauty salons and to sharpen knives as well.
These machines use a reversible 24VDC brushed motor or some occasions 90VDC with TENV armature and 13AMP.
Due to space issues inside the container, I need to use an AC/DC transformerless motor speed controller that also admits a switch at the output and before the motor to be able to change the current clockwise and counterclockwise.
I consider that you can design a type of controller like the one I need.
I await your response to provide you with all the information you need, photos and videos.
Thank you
Jose
Swagatam says
Thank you Jose,
You will need a 24V 13 amp SMPS power supply for your motor which will not be a small unit, it will be at least 8 by 5 inches in size.
The reverse forward operation of the motor can be simply done with the help of a DPDT switch.
Let me know if the above factors are OK with you?
Jose Zuria says
Hi Swagatam, thank you for replaying me.
Right now I have pictures of a unit I’m using, I’d like to send them to you so you can see what I think I need.
But where would I send the photos?
Thanks
Swagatam says
Hi Jose,
You can upload the pics to any online free image hosting site, and provide the link here.
Jose Zuria says
Hi Swagatam,
Here are links to the photos of the machine that I I use it regularly, it works well and the speed control makes the motor work well.
With something like this or a little better I would be happy, I don’t think I need more.
I tried to show you as much as possible that the PCB has, I hope it is. Enough, if you don’t tell me and I’ll see what to do.
The mosfets say: 54008L ODJH9
Capacitors: 104K 250L
Big Diodes: MCC 6 Au
Thrystor: 2N6027 424
https://we.tl/t-XtBsaoHAqB
https://we.tl/t-2UaRd4GeSz
This type of motor speed control is what I want since it works well, or at least that you suggest something different.
Thank you, I await your answer
Swagatam says
Hi Jose,
I can see the images now.
From your explanation, I guess you need a speed controller circuit along with a reverse forward control for your 24V 13 amp DC motor? right?
However the power supply unit of 24V 13 amp will be quite large which cannot accommodated inside the box that you have shown in the image.
Jose Zuria says
Hi Swagatam,
Here are the photo links:
//we.tl/t-XLBsasHAqB
//we.tl/t-ZVaRd4GeSz
In them you can see the machine that I usually work. The exterior measures 8x8x8 inches.
Inside you will see the motor speed control and two switches, one of them is the 110VAC outlet and the other is the one that controls the reverse foward of the motor.
In the photos I tried to see as much of the speed control as possible, but if it’s not enough, tell me and we’ll take others.
The mosfets say: 54008L ODJH9
Capacitors: 104K 250L
Large diodes: MCC 6Au
Trystor: 2N6027424
I hope this helps
Swagatam says
Hi Jose,
The image links are not opening, it is showing “page not found”
From your previous explanation it seems you want a reverse/forward control for your motor, and your motor specifications are 24V, 13 amp.
Is it right?
Saikat Ghosh says
Hello Swagatam sir
I am Saikat, I am using this website since last 2years for my projects purpose. Today I have tried the circuit for Speed control of 3-phase induction motor using zero crossing opto-coupler from https://www.homemade-circuits.com/3-phase-induction-motor-speed/ this site. But I can’t vary the speed of the motor using the pot. Can you help me out please? I am using BTA26 TRIAC instead of FKPF12N60 because this was unavailable.
Waiting for your reply
Swagatam says
Thank you Saikat,
Remove the PWM 555 connection from the optocouplers and try to switch ON/OFF the optocouplers manually through an external 5V or 12V. Make sure to use a series 1K resistor with the signal.
Please do this and check whether your motor is switching ON/OFF or not in response to these signals.
Saikat Ghosh says
THANK YOU SIR.
SAIKAT GHOSH says
March 30, 2023
Hello sir
I have tried this method by applying 5 to 12 v manually to opto-coupler but the motor runs without ON the opto-coupler and does not vary with ON/OFF condition.
Can you please give me the solution?
Why the motor is running without giving gate pulse to the TRIAC?
Please solve my problem.
Thank you.
Swagatam says
Hi Saikat,
when you apply 12V to the optocoupler, the motor should operate continuously, when you remove the signal the motor should stop.
The opto coupler triac circuit is taken from the datasheet so it should work.
Try separating the 3 optocouplers and check them individually with a bulb, and by supplying a manual ON/OFF signal to the LED side.
If it doesn’t work then the problem is with your oprocoupler circuit.
Swagatam says
Hi Saikat,
when you apply 12V to the optocoupler, the motor should operate continuously, when you remove the signal the motor should stop.
The opto coupler triac circuit is taken from the datasheet so it should work.
Try separating the 3 optocouplers and check them individually with a bulb, and by supplying a manual ON/OFF signal to the LED side.
If it doesn’t work then the problem is with your oprocoupler circuit.
Saikat Ghosh says
Hello sir
I separate the opto-coupler circuit and connected with the lamp using TRIAC but it doesn’t work then I tried a new opto-coupler but also the same thing happened.
Please tell me what should to do.
Swagatam says
Hello Saikat,
If the single optocoupler triac circuit is not working for you then unfortunately I cannot do anything, because it is directly taken from the datasheet of the optocoupler IC.
You can refer to any other datasheet such as this, all show similar switching diagram. I hope you have connected the external triac MT1, MT2 pins correctly??:
https://www.farnell.com/datasheets/1806097.pdf
Maurice says
hi,
I have a little challenge for you, if you accept.
here the specs:
I want to make the same ammo counter display of the M41a (Aliens gun)
* 2 digits
* counting down from 99 to 00 by hitting the trigger (1 digit with one clic and decounting by maintening the trigger)
* Time between each digit down : 1/4 second
* and lastly, a reseting button to 99
(sry for Bad english, I’m french)
thx Maurice
Have a nice day
Swagatam says
Hi,
You can try searching for “2 digit up/down counter circuit”, you will be able to find one.
Fred says
Hi;
I have a project that I need help creating the circuit and designing the circuit board.
I’m also willing to pay someone to help with this as it’s above my electrical engineering levels.
This is what I’m trying to create, a simpler version of this weed killer: https://rootwave.com/portfolio-item/rootwave-pro/ Their portable version uses a generator and runs on 220v, but I think for average garden weeds, a lower power version running on 120v (60hz where I live) would do nicely.
After reading a lot about it and their research, I found somewhere that their patients are for weed killers over 18KHz at 2K to 5K volts.
I’ve spent a lot of time selecting some of the main components I think will do the best job but need help in creating the full-bridge circuit.
I’m targeting an output at 18KHz, 5000v with an input of 120v 60Hz for the weed fryer. I may like to tap the output transformer midway too, so as to have a mid and high output voltage.
Main transformer core: Ferroxcube U126 x 2 pieces. Core material 3C94. Primary 24 turns 12 or 14 awg Lizt wire, Secondary 1000 turns 22 awg solid wire. I’m assuming for this type core, I can make 2 forms from some type of thin cardboard, one for each side, and have the primary on one side and the secondary on the other.
Controller: Unitrode TI UC3856N (PDIP-16 package) improved current mode PWM controller since it has current feedback. I already have these.
2 IR21834 Half-Bridge Gate Drivers to form the full-bridge (PDIP-14 package). I already have these.
4 IRF300P226 MOSFETs. I already have these.
Current Sensing Transformer: Ferroxcube Toroid TX22/14/6.4-3E27, maybe 75 turns of 26awg for the secondary (I’m not 100% sure about the number of windings here).
I think a probe made from 1” PVC pipe with a brass tip would work. I plan on connecting the probe to the output of the transformer with high voltage flyback wire as it’s well insulated. I also plan on a trigger type switch on the probe that will turn the power on and off.
The example circuit in the datasheets for the UC3856 (I think the example is in the datasheet for it’s predecessor the UC3846) obviously do not contain all the required components to create a working circuit. That’s where I need help.
Does anyone have any interest in helping?
Or, maybe someone has a better idea to do this with, or, knows of something that would work with a few modifications.
Thanks,
Fred
Timothy J Lincourt says
You designed the Door Intrusion Indicator circuit at the link below for Mr. Azhan on another website.
https://www.brighthubengineering.com/diy-electronics-devices/121484-simple-thyristor-circuits-explained/
I want to modify this to let a deaf person in another room know when the doorbell rings. I’m replacing the door switch with a relay activated by the doorbell. But my doorbell uses 12 volts. I would like to know if I would need a different thyristor if I use 12 volts instead of 9 volts, as in your circuit?
Swagatam says
Sure, you can use that circuit for your specific application.
You can use 12V with the circuit without any modifications, no issues at all.
To illuminate an LED any small thyristor would work, You can even try BT169 which is quite small in size.
Ray R. says
I just recently found your site and think it`s great! I have found all kinds of new interesting projects to try out. So I want to thank all of you. Anyways, I just wanted to mention that I was trying out your (Using a Joule Thief Circuit) in the (4 Simple Power Bank Circuits for Mobile Phones) article and wanted to mention that the circuit images should be corrected to show that the primary and secondary of the toroid transformer should be hooked up in opposite directions. A dot at the top of the primary and a dot at the bottom of the secondary or vice versa is usually used to indicate this. I have also seen this same circuit in several other project articles too which did not note this either. Thanks again and keep up the great work.
Swagatam says
Thank you very much for liking this site.
I agree with you, a dot should have been put across the winding to indicate its polarity.
However, I think I have already mentioned in the article that if the circuit does not seem to work initially you can simply try swapping one of the winding ends to correct the issue.
Ray R. says
Sorry, I did not see that you had mentioned that. By the way, that circuit works nice. Thanks.
Swagatam says
Thank you so much for your kind feedback!
Carlos says
Hi Mr. Swagatam, thanks for your quick response, sorry for my ignorance but could you give an example with a circuit (drawing)… What I need is… 5vdc input voltage. Then I need a voltage of 1mv on one side and 55mv on the other side. Thank you so much.
Swagatam says
Imagine there are 3 resistors in series with your 5V supply R1, R2, R3. R1 is on the positive supply side, R2 is at the center and R3 is on the negative supply wire of the supply.
You want two outputs, one after R1, and one after R2.
The following two equations can be used to solve them. Here Vin = 5V
Vout (between R2, R3) = Vin[R3/(R1+R2+R3)]
Vout (between R1, R2) = Vin [(R3 + R2)/R1 + R2+ R3]
Carlos says
Hello good afternoon my name is Carlos and I am a faithful follower of the website, I want to know if how to make a resistive divider but with 3 resistors, that is, 2 different voltages. Would you have any formula or calculator for this purpose? From already thank you very much.
Swagatam says
Thank you Carlos,
Let’s consider the 3 resistors are in series R1, R2, R3, R3 being the ground side resistor.
Then the voltage between R2 and R3 would be:
Vout = Vin[R3/(R1+R2+R3)]
Voltage between R1, R2 would be
Vout = Vin [(R3 + R2)/R1 + R2+ R3]
Akshay says
Hi,
I wanted to design a wireless power transfer circuit at a power rating of 100w. I had gone through your design for “High Current Wireless Battery Charger Circuit”, but I wasn’t sure whether this would handle a 100w rating. Could you suggest changer or an appropriate circuit to handle this load?
The objective is for an economical design rather than high efficiency. (The coils can be very close to each other)
Thanks in advance.
Swagatam says
You can basically do it with some trial and error.
Take a 555 IC configured as an astable oscillator circuit.
Connect a mosfet driver at its pin#3. The mosfet could be an IRF540.
After this connect a 30 turn pancake type coil with the mosfet drain. Now adjust the frequency of the 555 IC such that there’s minimum heat on the mosfet.
Make an identical 30 turn coil for the receiver, rectify the output with a diode and a capacitor to get the wireless power transfer output.
Vikram M says
Hi again Swagatam sir
Hope you are doing well. Kindly help me in this regard.
I need to power Arduino Nano and ESP32 Module to via motorcycle’s 12V Lead Acid battery while the bike is in running condition.
Can this module be used directly connected with battery terminals to provide a safe and stable voltage to Arduino and ESP32:
IC IP6505 or MH-KC24 based USB Fast charger: https://www.homemade-circuits.com/wp-content/uploads/2023/03/usb-fast-charger.jpg
(This contains over and under voltage protection)
The bike battery offers fluctuating voltage (9-15.5V, even lower during cold cranking) and there may also be voltage surges/transients upto 100V.
Swagatam says
Hi Vikram,
From its description it seems it can be connected directly with batteries for the buck converter operation. But I am not sure whether the output will be a constant voltage or not, if it is a constant voltage then you can use it to power your Arduino and ESP modules.
abdulkarim says
sir please how to make simple battery charging level indicator e g 1 led 25 2 led 50 4 led 75 4 led 100 parentage full so how to make it
Swagatam says
You can try one of these circuits:
https://www.homemade-circuits.com/3-step-dc-voltage-level-monitor/
abdul says
how to make simple battery level indicator circuit
charging level use led
christie says
Someone keeps using my email to make comments and not their own email. i’d like this to stop before i consider this harassment
Swagatam says
I checked my database and found the same email ID as yours used by someone called Chris. I will give his IP address to you so that you can complain against this guy to the cyber crime department.
His IP address is 160.119.108.72
Vikram M. says
Requesting Your Help: Powering Up Arduino with 12V Motorcycle Battery
Hi,
Hope you are doing well!
I read your article/guide here: https://www.homemade-circuits.com/how-to-design-power-supply-simplest-to/
I am working on a project and was wondering if you could provide some help/support?
I need to power the following projects/components directly via my motorcycle’s 12V Battery (the same battery would be powering all the bike’s electricals)
1. Reverse camera + GPS (Fitted at back of bike, rear facing)
Parts used:
– ESP 32 Cam module
– NEO 6M GPS Module
Application:
To keep an eye on the vehicles coming from the rear end
2. Proximity sensor (Fitted at back of bike, rear facing)
Parts used:
– Arduino Nano
– HC SR04 sensor
– Buzzer
– Red LED
Application:
To detect vehicles coming from the rear end and activate the buzzer and led if vehicle comes in a certain range of distance.
My question:
– What is the safest way to hook up the above 2 circuits with the bike’s battery terminals? As you may know, the bike battery offers fluctuating voltage (9-15.5V, even lower during cold cranking) and there may also be voltage surges/transients upto 100V.
Motive: I want to provide a safe, stable, clean power source to my circuits.
Any help would be appreciated. Thanks in advance.
Swagatam says
If there is a danger of 100V spikes then you should try a shunt type regulator circuit such as the following one:
https://www.homemade-circuits.com/wp-content/uploads/2019/07/shunt-3.png
To make the output even more filtered you can add a 2200uF/25 V across the supply rails.
You will have to adjust the 3k3, 4k7 resistor values appropriately so that the desired output voltage can be achieved across the output terminals.
Vikram M says
Thanks, will this be suitable for DC?
Currently the image seems to have AC power source.
Swagatam says
The alternator output is converted to DC by the rectifier diodes, so the ultimate output to the circuit can be a DC.
Just make sure the maximum DC current is much lower than the transistor’s collector/emitter current handling capacity.
For example the TIP147 has 10 amp max current handling capacity, so the input DC should be less than 5 amps.
HERMAN says
Dear Swagatam,
I am interested in your FREE ENERGY FROM INVERTER as you described on you website:
https://www.homemade-circuits.com/free-energy-from-inverter/
Please advise how to replicate your circuit. Or do you sell the inverter described in your article?
Swagatam says
Hi Herman,
It was proved by many readers that it is not a free energy, please read the comments under the post.
Vishwa Mukh Bharadwaj says
Sir,
Good evening,
I am trying to connect output from a mono tape recorder to a laptop. An ADC module PCF 8591 is available on a website.
Will it do the job please.
Thanking you for your time,
yours faithfully,
Swagatam says
Hi Vishwa,
Sorry, I am not sure about it because I use a computer and have not used a laptop so far!
Miguel says
Hi,
So for the buck converter you built here https://www.homemade-circuits.com/buck-converter-using-arduino/
How can I use the same 9V source to power the Arduino as well?
Thank you,
Miguel
Swagatam says
You can see the 12V battery in the first circuit diagram. You can use the same battery voltage to power the Arduino through a 7809 IC
Mike says
Hello Sir, I’m working on a school project and I’m currently stuck. I’m working on a smart irrigation system using Arduino and a GSM module.
The connection is okay and all the sensors are working already but I’m having problems with programming the GSM module. Currently it can send messages to my phone but when i send a message to the number in the module it doesn’t recieve/display it on the serial monitor.
Pls i need your help on this.
Swagatam says
Hello Mike, unfortunately, I am not an Arduino expert, so solving your problem can be difficult for me.
By the way I have a related post in the blog, which you can refer to through the following link:
https://www.homemade-circuits.com/gsm-pump-motor-controller-circuit-using/
Mike says
Ohh okay
I’ll check the post out
Lennart says
Hey,
I have to build a university project and we haven’t had any electricity classes, but I still somehow build an elevator. I did some research on 555s already and I basically want to make a 555 sr latching circuit that has a LDR as a set input and a IR sensor as a reset. So a golf boll rolls in a box, triggers the light sensor which stays at the bottom, but triggered a DC motor over the 555. As soon as the elevator Box reaches the right level it triggers the IR and resets the 555 latch.
I technically know how to make a 555 sr latch, but I am not sure on how to integrate the 2 sensors 🙁 could you help me? You would literally safe me and I am super curious about electronics and I really want this project to work!
If this really works, you an incredibly amazing person!
Kind regards,
Lennart
Swagatam says
You can try the following circuit:
https://www.homemade-circuits.com/wp-content/uploads/2023/03/555-set-reset-with-photodiode-and-LDR.jpg
For further questions, please comment under the following post:
https://www.homemade-circuits.com/set-reset-circuit-using-ic-555/
Wael says
just recently found your blog and upon further reading your post it’s very helpful and I appreciate your work.
I have a project in mind but I am stuck with it, My idea is how can I charge 12VDC 12A 28pcs battery in series connection with balancing charger? Can you help me with it
Swagatam says
Thank you, and glad you liked the blog. I have a balance charger circuit, but it is not a tested one. Here is the link for it:
https://www.homemade-circuits.com/lipo-battery-balance-charger-circuit/
Abdul says
Please help me how make simple charger 5v after battery fully so circuit is switch off the input
Swagatam says
You can try one of these circuits:
https://www.homemade-circuits.com/usb-automatic-li-ion-battery-charger/
abdul says
sir used irf 3205 instead of tip 122 pleas
e their is no problem
Swagatam says
MOSFET will not work for a 5V circuit, you must use TIP122 or a 5V relay.
ahmed khan says
I am trying to make a battery charger specifically or li-ion batteries (20700). Configured in a way that, there are 20 cells in series to make one stack (72volts), and 5 of these stacks are in parallel to increase rated current to (15AH). I have made a charger before but its for only single cell in which i used two voltage regulators and Arduino as controller to switch between CC/CV. But facing issues in making it for 72v, input voltage is 220Vac, my desired charger rating is 72Vdc, 12Amps
Swagatam says
You can try the last circuit from the following article:
https://www.homemade-circuits.com/make-this-48v-automatic-battery-charger/
Just make sure to use 330 ohm 2 watt for the base resistors of TIP36
The second transistor with TIP36 can be BD140
The BC546 should be also replaced with BD139
use a transformer to step down the 220V to 72V DC
Anuraj Ana Vathukkal says
Hello Swagatam,
I would like to make a small vacuum chamber and I would like to use a 12 V relatively cheap diaphragm pump. I know it’s unreliable, but I don’t have much budget to make this. So I would like to have a vacuum on-off switch to automatically switch on & off the diaphragm pump to maintain the vacuum pressure. You know continuous working may damage the pump, which will help to increase the life. I was not able to find a simple solution for vacuum pressure. Hope you can support me on this. I found one DIY product online but no guidelines to build our on and they are selling it in the US only.
Swagatam says
Hello Anuraj,
You can perhaps try implementing the following circuit. The PWM pot could be used to adjust the ON/OFF rate of the 555 output relay:
https://www.homemade-circuits.com/wp-content/uploads/2023/02/555-pwm-with-relay.jpg
You may have to further experiment by changing the 47uF capacitor until the desired ON/OFF timing is achieved.
Anuraj Ana Vathukkal says
Thanks, Swagatam for your quick response.
Actually, I don’t have a fundamental knowledge of electronic circuits and IC’s. I love to do DIY this and I learn from that. So google helped me to find out the full form of PMW in IC and it will be great if you can explain it a little bit more considering my limited knowledge.
I have a few doubts.
1. Where I can attach a vacuum pressure sensor to measure the real-time pressure of the vessel and activate the pump accordingly.
2. Normally what type of value is sent from a vacuum sensor? For example resistance / capacitance
https://www.homemade-circuits.com/wp-content/uploads/2023/02/air-pressure-sensor.jpg
3. Can I use the above sensors to measure the vacuum? If yes How can I integrate this into the circuit?
Hope you understand my level of knowledge. Awaiting for your response.
Swagatam says
Hi Anuraj,
Frankly, presently I do not have any idea regarding how a vacuum pump and air pressure sensor modules practically work and how these can be implemented in real life. I will have to study them.
You said that you wanted to switch the vacuum pump ON/OFF at a certain interval so that it does not get damaged by a continuous supply, therefore I designed the PWM circuit.
The relay contacts in the circuit can be used to switch your 12V vacuum pump ON/OFF at a given frequency depending on the value of the capacitor and the adjustment of the pot.
PWM stands for pulsed width modulation.
It is the amount of ON time and amount of OFF time that can be produced from pin#3 of the IC 555.
So by adjusting the 5 K pot you can uniformly adjust for how long the relay can be kept ON and for how long the relay can be kept switched OFF. In short, you can vary the On time and OFF time of the relay as per the requirement of the vacuum pump.
Anuraj Ana Vathukkal says
Thanks for the response. Basically I want to make a machine with small vacuum chamber. Some more DIY concepts on mind but don’t have much knowledge to make that practical. Anyway thanks for your valuable time.
Swagatam says
I think you can try any small 12 V vacuum generator and see how it works. All the best to you.
Shogun Billings says
Can you design a AC to AC SMPS for following conditions:
Input 380-480 VAC
Output 50 VAC output, 50/60hz,
Size: 3500va
The power supply would need to robust enough to be cycled up 300 times per hour, it would be used to replace two transformers used for impulse sealing. It would need to be designed to work with Ropex Sealing controller, model 5011
Also, would need to get it UL listed.
What would it cost to design and phototype?
You can email me directly.
Swagatam says
Sorry, SMPS is a very difficult circuit, it won’t be possible for me to design it for you.