ON OFF Toggle switch circuit diagram using IC 4017
A toggle switch can use to ON and OFF the load alternatively with the incoming pulses. That is, to act as a push ON and push OFF switch.
The circuit uses a decade counter IC 4017, which counts each positive edge triggering pulse (here we provide by push switch). In the initial state, the output at pin2(output 1) is low. After the first pulse, the counter obtains a high output at pin 2. As the reset pin15 has connected to the pin4 (which is output2), the counter resets for the next pulse. And this process repeats for each pulse. Thus, the circuit obtains the output at pin2, to repeatedly ON and OFF with each positive pulse at the pin14.
The output current of an IC 4017 has just a few milliamperes. So, in order to use the toggle circuit with high power loads, we are driving the output through a transistor. For loads that can be operated with the same supply, we can directly drive the load through a transistor. That is, the position of the relay can be replaced with a load. On the circuit, the output is arranged to drive an SPST relay for loads with an external supply.
IC – 4017
Resistor – R1,R2 – 10k, R3-1K
Transistor – Q1 – BC547
Diode – D1 – 1N4007
Switch – S1-push switch
Relay – SPST – 12V,200ohms
Supply – 12V