Simple Single Push Button ON OFF Relay Circuit

In Some Case, To control Some Electronic or Electric Load we need Single switch like Push button and we start or stop the function of load with one single Push. To Construct Push ON Push OFF Circuit we don’t need to depend on Microcontrollers or timer ICs, we can built Simple Single Push Button ON OFF Relay Circuit by using few transistors and a Capacitor.

Here Push button ON OFF circuit Constructed to turn ON OFF Electric load connected with the Relay. We can construct this circuit in common PCB. All components used in this circuit are through hole components.

Circuit Diagram

Components Required (BOM)

1Q1,Q3Transistor BC547BTA – TO92 package – NPN2
2Q2Transistor BC557BTA – TO92 package – PNP1
3RLY1Relay JSM1-9V-51
4R1, R2Resistor 470KΩ2
5R3, R4, R5Resistor 10KΩ3
6R6Resistor 1KΩ1
7R7Resistor 910KΩ1
8R8Resistor 100KΩ1
9R9Resistor 560Ω1
10R10Resistor 10Ω/1W1
11C1Capacitor 1µF/50V1
12SW1Tactile Push Button Switch1
13D1LED Green 5mm1
14D2Diode 1N40071

Construction & Working

This Circuit Operates in 9V DC power supply hence we used 9V Relay, and you can choose Relay depends on the operating voltage you applied to this circuit (It can operate with 3V to 12V DC). Capacitor C1 holds the voltage flowed through Resistor R1 and transistor Q1 connected between R1, C1 elements, to discharge voltage when push button pressed. When Push Button pressed the voltage stored in C1 flows to the Q3 transistor base through R6 and turn ON Q3. LED and Relay Connected to the collector terminal of Q3 gets Ground supply and gets turn ON.

When push button pressed during ON condition Q2 transistor allows positive voltage to the LED and Relay through R8 and makes the LED and Relay turn OFF. This operation repeats whenever the push button switch pressed.

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