This is 2 Digit Simple digital counter circuit using CD4026 as main parts can display with LED 7 segment 0-99 number There is a reset button to restart. It can be applied to, for example, counting products, counting people into the library, and more.
The working principle
As circuit in Figure 1. The IC1, IC2-CD4026 4026 IC CMOS Counters Decade/Divider / Integrated Circuit by this IC number can drive LED 7 segment directly. Which them connected together by IC1 is a unit counter IC and IC2 is ten digit ten counter and both IC will works at Rising edged CLOCK only.
The input signal will connected to pin 1 of IC1 and signal will go out at pin 5 of IC2 to send to next digit sequence. To at pin 15 of both ICs will connected together to reset. When want to restart again.
The working this IN point will must to connect to center point. By this point need to provide a positive voltage lower than 2 volts.
When there are input signal come in, lower voltage than 2 volts. The voltage will sent to D1, R1 in to base of TR1, TR1 so conduct current, when TR1 conduct current TR2 also will conduct current by bias current through R2 and pin 1 of IC1 will have CLOCK feed to IC1 will begin count 0 again.
When input signal into a continuous, IC1 will count indefinitely. When CLOCK signal into a 10 cycle. Which will count the number 9, then it changes to a new number 0. This at the same time will send signal out off pin 5 and will send to pin 1 of IC2,
IC2 is ten digit counter, will start at “1” You will maintain this state indefinitely, until IC1 count of 0-9. Signal at pin 5 of IC1 sends a signal to Pin 1 of IC2 again. IC2 also goes into counting second. And maintain this state indefinitely, again until IC1 to count from 0-9. Will be output at pin 5 of IC1, send it to pin 1 of IC2.
IC2 also goes into counting third, the work will be to look like this again.
Which from the circuit of Figure 1 to counting maximum of 99 only.
If I need to count more than this, it can be connected to it.
If you want to make a new start, press RESET. Number is the 00 and if input signal in to this will start counts new again.
Now at LED 7 segment DISPLAY indicate as number 00. But if is others number to press reset switch at DISPLAY will show is 00, then test press TEST switch at DISPLAY will show 01, 02, 03 continue to 99. Then return to 00. The pressing switch continually.
If to make the switch back to 00, press RESET switch. When tested as follows show that this circuit can operate normally.
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