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4-Digit Counter Module Schematic Circuit Diagram

Efficient Repetitive Task Execution with Counter Modules

Counter module offer uncomplicated and versatile subsystems, enabling individual components to execute repetitive tasks on nearly every clock cycle. They frequently serve as replacements for specific peripheral driver hardware, minimizing the number of components necessary in an application.

Versatile Four-Digit Digital Counter

This condensed four-digit digital counter is applicable in various contexts, including clocks, frequency meters, digital voltmeters, tachometers, stopwatches, scoreboards, and more. Equipped with a reset switch and a carry output signal, this counter module ensures efficiency and flexibility for diverse applications.

The maximum count of the module depends on which version of the IC is used:

  • The MM74C926 pulls its carry output high when counter state 6000 is reached. The IC counts to 9999.
  • The MM74C927 is like the MM74C926, but the second most significant digit divides by 6 rather than by 10. Thus, if the clock input frequency is 10 Liz, the display would read minutes, seconds, and tenths of seconds. e.g. 9:59.9.
  • The MM74C928 is like the MM74C926, but the most significant digit divides by 2 rather than by 10. Also, the carry-out is an overflow indicator that goes high at counter state 2000 and goes low only when the counter is reset. Thus, this is a 3 1/2 digital counter.

CMOS-based Display Multiplexers

All three MM74C92x ICs are designed as CMOS devices. Each IC incorporates an internal display multiplexer, requiring only four external switching transistors connected to the common cathode connections of the 7-segment LED displays. The multiplex frequency is set at approximately 1 kHz. Additionally, the carry-out terminal can be utilized for cascading multiple counter modules. These ICs have a current consumption rate around 100 mA.

Voltage Limitations and Supply Range

It’s essential to note that clock input signals surpassing the module’s supply voltage should not be permitted, and they must not exceed 15 V. The acceptable supply voltage range for all three MM74C92x ICs used in this context is between 3-6 V, as specified in the data provided by National Semiconductor data sheets.


Solderless Breadboard,
Arduino Uno,
4 Digit 7Segment Display Module TM1637,
Push Button x 3,
Male to Male Jumper Wires,
Male to Female jumper Wires,
Battery clip,
Battery 9v

Parts list

  • R1-R4:R12 = 1.5 kΩ
  • R5-R11 = 56 Ω
  • R13 = 10 kΩ

Capacitors: C1:C2 = 100 nF
Semiconductors: T1-T4 = BC547B

LD1-1,D4 = HD1107

Integrated circuits: IC1 = 74C926/927/928 (see text)
Miscellaneous: S1 = PCB-mount push-button

K1 4-way PCB header

4-digit counter module Schematic diagram

4-digit counter module Schematic diagram

4-digit counter module Schematic diagram


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