The proposed 00-99 digital pulse counter circuit becomes very handy in places where you need to keep the people organized in some specified order.
Operating details of the digital counter
As may be referred the circuit employs the popular 555 IC to genearte the pulse clocks. The pulse counting is done with the help of SW1. A couple of CMOS ICs 4026B respond to these clocks and become directly responsible for running the 7-segment display.
Since the last digit is restricted to 99, the first 4026 activates the second, when it crosses from 9 to 0. (see the pin 10 of the first 4026 that enters the clock input of the second).
When the circuit is first powered, it may not start its count from a zero, so a momentary reset activation becomes necessary and is implemented using the switch (SW2). Pressing this switch the account resets the circuit and starts the count from zero (00).
It may be interesting to see that a pulse is applied to pin R "RESET" in each integrated circuit.
Circuit Diagram
Parts List for the discussed digital counter circuit
- IC1: 555
- IC2 = IC3 = 4026B
- DS1 DS2 = = 7 segment display
- C1 = C2 = C3: 0.047uF
- R1: 10K 1 / 4W
- R2: 1M 1 / 4W
- R3: 33K 1 / 4W
- Switches SW1 = SW2 = normally open push to ON switches
0 to 99 Counter using IC 4518, and 4511
The circuit using ICs 4518, 4511, and a common cathode display is a binary counter with a decimal output. It can count from 0 to 99 and display the count on a 7-segment display.
The IC 4518 is a dual BCD (binary-coded decimal) up-counter, which means it can count up in decimal from 0 to 99. The two counters are cascaded so that the second counter counts up by 1 every time the first counter reaches its maximum count of 9.
The output of each counter is connected to a BCD to 7-segment decoder IC 4511, which converts the BCD code to the corresponding 7-segment display code. The outputs of the decoder are connected to the corresponding segments of the display.
A common cathode display has a single cathode connection for all the segments. The cathode is connected to ground, and the anodes of each segment are connected through a current-limiting resistor to the outputs of the decoder.
When the circuit is powered on, the counters are reset to 0, and the display shows "00". Every time the count reaches 99, it resets back to 0, and the display starts counting again from 00.