Simple Seven Segment Counter Circuit

Think about a device that records events by repeatedly pushing a button.

This is what an electronic counter does.

A customized display that looks like a little calculator screen shows the amount of clicks.

There has been a lengthy history of use for these counters!

What is a Seven Segment Counter Circuit:

An electrical circuit called a seven segment counter circuit is made to count and show numerical values on a seven segment display.

The seven segment display uses seven separate segments organized in the shape of the number “8” to show the numbers.

Different numeric digits 0 to 9 is shown randomly by flashing these parts which are selected from a to g.

Circuit Working:

Parts List:

The displays LED configuration creates the shape of the number eight in decimal form.

The matching LED flashes and displays decimal digits 0–9 in response to a signal received at the input pin.

In addition being included into LCDs seven segment displays are used in a variety of circuits for displaying data.

They are usually used directly with low voltage devices and are available in two forms: cathode type and anode type.

This article describes how to build a basic circuit for a seven segment display counter using a 555 integrated circuit, a decade counter IC 4026 and a common cathode seven segment LED.

When the count key is pressed the 555 IC which is configured as a monostable multivibrator produces a pulse.

The IC 4026 receives this pulse as input counts each pulse and adjusts the seven segment LED accordingly.

When pressed the switch button which is connected to the IC 555s trigger pin provides a negative input.

The timing frequency produced by the timer IC is controlled by the timing resistor R2 and timing capacitor C1.

The pulse is connected to a balanced bias through resistor R3 and capacitor C2.

The monostable pulse serves as an input to the IC 4026 decade counter which activates the seven section LED and increases the counter value with each pulse.

The count cycle is repeated from 0 to 9 for every input received or the count value is reset by pressing the reset button.

Formulas:

One can build a seven segment counter circuit with the components shown in the circuit diagrams above mainly by using the 555 IC to supply clock pulses and the 4026 Decade Counter IC to drive the seven segment display.

The circuit design formulas are provided below:

A 555 IC-Based Astable Multivibrator:

The 555 integrated circuit will supply the clock pulse to the 4026 counter.

The oscillation frequency is controlled by the resistors and capacitors connected to the 555 while it is in astable mode.

Frequency Formula:

f = 1.44 (RA + 2RB) * C

where,

• The resistors that are connected to the IC 555 are RA and RB.
• Connecting pin 1 to ground and to pin 6 threshold is done by capacitor C.

Get the right numbers for RA, RB and C to set a certain frequency.

How to Build:

To build a simple seven segment display counter circuit follow the below mentioned steps:

555 Configuration:

• Connect pin 8 of the 555 IC to positive supply.
• Connect pins 2 and 6 together and join them to ground.
• Connect pin 5 to ground.
• Connect pin 4 to pin 8 through resistor R1.
• Connect pin 2 to ground through capacitor C1.

Decade Counter IC 4026:

• Connect pins 13 and 14 of IC 4026 to positive supply.
• Connect pin 15 to ground.
• Connect pin 1 to positive supply.
• Connect pin 5 to pin 3 of the 555 timer IC.
• Connect pins 2, 3, 4, 7, 10, 11, and 12 to the corresponding segments of the seven segment LED display.
• Connect pin 6 to ground through a resistor R2.
• Connect pin 7 to positive supply.
• Connect pins 8 and 9 to ground.
• Connect pin 16 to positive supply.

Timing and Switch:

• Between pin 2 of the 555 IC and ground connect the push button switch.
• Join capacitor C2 and resistor R3 between pin 6 of the 555 IC.
• Connect the R3 and C2 junction to ground.

Source of Power:

• Connect the circuits positive and ground supplies to the power source.

The Reset Button:

• Connect the reset button between IC 4026 pin 6 and ground.

Testing:

• Power to the circuit.

• For the seven segment display to begin counting press the push button switch.
• To reset the count press the reset button.

Take note:

• To prevent any possible problems handle components with care and verify connections twice.
• It is best to ask an experienced person for help if you are new to electronics.

Conclusion:

Digital counters, timers and other devices where counting and numerical display are vital often use the Seven Segment Counter Circuit.

A key component of digital electronics is often used in educational projects to show the basics of digital circuits.

References:

Frequency counter

Using a Frequency Counter