Electronics counter

Simple counting can be done by anyone but counting in interval up to large number is tedious and the chance of forget is maximum. As, we have already published Counter Circuit | Digital Counter. Now , here electronics counter is second project by dreamlover technology in the series of counting based project. Bothe the counting circuit published in this website counts up to 10,000 with the help of four seven-segment displays. The difference is previous circuit utilize CMOS ICs where the electronics counter use TTL ICs.

Circuit description

The entire circuit of electronics counter is divided into three main section :- input, display and driver or decoder section.

The input circuit consists of LDR following by negative square wave generator circuit build around Timer IC (NE555). A bulb is used here as light source focused on LDR. The property of LDR is that whenever the light focused on base of LDR is obstructed, it gives trigger and square wave is generated and given as input signal to counter circuit. So the objects to be counted are arranged in a row to move one by one in between the light source and the LDR.

 circuit diagram of ldr operator

IC2 shows any number between 0-9 according to input square wave given to pin no 14. After each negative pulse a carrying pulse is produced by decoder IC and given to another one (i.e. from IC2 to IC3, IC3 to IC4, IC4 to IC5 ). IC5­ and IC6 is BCD to 7-segment latch decoder driver. The reset switch SW1 is used to reset the electronics counter to 0000 states.

circuit diagram of electronics counter decade counter

Resistors (all ¼-watt, ± 5% Carbon)

R1 = 1 KΩ

R2 = 100 KΩ

R3 – R30 = 180 Ω

VR1 = 100 KΩ preset


C1 = 4.7 µF

C2 = 1000 µF/10V

C3, C4 = 0.1 µF


IC1 = NE555 (Timer IC)

IC­2 – IC5 = 7490 (Decade and Binary counter)

IC6 – IC9 = 7447 (BCD to 7-segment decoder)

IC10 = µA 7805 (Voltage Regulator)

D1 – D­4 = Display FND 507


Mic1 = Microphone

B1 = Bulb




Related Project

  1. Advanced LED Temperature Indicator use of a V/F converter in monitoring temperature in degrees Fahrenheit (0F).
  2. Counter Circuit | Digital Counter Counter using CMOS ICs , counts up to 10000
  3. Twilight Lamp Blinker indicate obstruction by blinking in adjusted time
  4. Multi-Mode Running Light used in ceremony, can operate in three different mode
  5. Digital Mains Failure/Resumption Alarm indicating AC mains fails or resumes by producing alarm sound

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