555 Precision Timer Tester Circuit

Contents hide

NE555 precision timer IC is one of the most important precision timer IC. There is a huge list of projects that can be built by using 555 Timer ICs. NE555 Timer IC is also considered to be an ideal IC since it offers multiple features like multipurpose functionality, low power consumption, small size, and durability. In this project, we are going to design a simple 555 Precision Timer tester circuit.

This 555 Precision Timer tester, allows us to make sure that this integrated circuit works properly.

Hardware Components

You will need the following parts to build this circuit.

S.no	Component	Value	Qty
1.	precision IC	NE555 timer	1
2.	Resistor	69KΩ, 40KΩ, 390Ω	1,1,1
3.	Capacitor	1μF, 10nF	1,1
4.	Battery	9V	1
5.	Connecting Wires	–	1
6.	LED	5mm	2
7.	Breadboard	–	1

555 Timer Pinout

Pin No.	Pin Name	Description
1	GND	Ground
2	TRIG	Trigger, set to 1/3 of Vcc
3	OUT	Timer Output
4	RESET	Reset active low
5	CONT	Comparator threshold control
6	THRES	Threshold, set to 2/3 of Vcc
7	DISCH	The low impedance discharge path
8	Vcc	Chip supply voltages (6v-12v)

Circuit Diagram

Working Explanation

In this circuit, the NE555 is wired as an astable multivibrator. On completing the circuit, the LEDs D1&D2 will flash alternatively. That is when the output is high D1 will glow & when the output is low D2 will glow. The frequency of flashing will depend on components R1 (69KΩ), R2 (40KΩ) & C1 (1μF).

When there is a continuous supply, C1 will start charging through R1&R2. When the voltage across C1 gets above 2/3^rd of the supply voltage the internal Flip Flop toggles. Pin 7 becomes low & C1 starts discharging. When the voltage across C1 goes below 1/3rd of the supply voltage the internal flip flop resets & pin7 becomes high. The C1 again starts charging. All these operations will take place if the IC is healthy. According to the frequency of this charging & discharging, the LEDs will flash. Through this procedure, we can conclude if the IC is healthy or not.