Triacs are one of the most important active electronic components which are exclusively used for power switching applications, these devices are especially suited to AC mains loads, and are able to switch large currents consistently.
Triacs are the solid state replacements to mechanical relays, and come configured as static relays.
The modern triacs today are highly sophisticated with their specifications and make, one such example is the BTA41, 600B, I have explained its technical specification and datasheet from the following points:
Identifying Print Value of BTA41/600B
- BT indicates series number,
- "A" represents that the device is insulated, while B would mean non-insulated. The insulation is provided on the Tab of the device upto 2500 volts.
- 41 = 4 and "one" zero, that equals 40 Amps
- 600 is the voltage handling capacity, therefore here it's 600 volts.
- B represents the triggering sensitivity that's 50mA in this case
- Absolute Maximum Rating (at around 25 to 40 degrees Celsius)
- RMS, continuous current handling capacity = 40 Amps
- Non repetitive peak current = 400 Amp, only for max 20ms.
How to Connect
The pinouts are connected just as we connect other normal triacs. I have explained them yet again:
A1 should be always connected to ground. The ground doesn't have to be necessarily the neutral of the AC, it can be any one wire out of the two mains input.
The other wire will go to one of the load terminals, while the second wire of the load will go to A2 of the triac.
The gate should be connected with the desired trigger input which must be a DC, because the triac will conduct with every rising positive edge of the DC trigger.
Here the minimum triggering gate current is 50 mA.
A1 should be made common with one of the AC terminals as well as the ground of the DC trigger circuit, in case an external triggering circuit is incorporated.
Application Notes
As suggested in the above sections, the triac BTA41/600B is best suitable for applications concerning control of AC loads such heater coils, high power halogen lamps, AC motor pumps or simply motors such as in dryers, blowers and so forth.
The following circuit illustrates how the device may be utilized for controlling heater coils such as in furnaces, induction cookers etc.
The above circuit can also be used for controlling AC motor speeds simply by replacing the heater coil with the motor wires.
The adjoining diagram depicts another application of BTA41/600 where it has been configured as a PWM assisted AC motor controller or even heater coils.
WARNING: The above circuits are not isolated from mains AC, and therefore are extremely dangerous to touch in open and powered condition.