Mosfet Switch: How to use Mosfet as a switch
As we all know, a Electronic Switch is a device which has two states, ON and OFF. Similarly, we can implement a switch with the help of Mosfet. As we all know a Mosfet has 3 states, Ohmic, Saturation and Cutoff states. We can operate mosfet in Cutoff and Saturation state of Mosfet to help it work as a Switch. A Mosfet switch when acted upon gate supply above minimum threshold works as ‘ON’ and when there is no gate supply it works as a “OFF”. Let us study about How to use Mosfet as a Switch.
- We will use N-Channel Mosfet [2N6000]. If you are new and unaware about the working of a N- Channel Mosfet check out this article: N Channel Mosfet Characteristics and working.
Circuit Diagram: Mosfet as a Switch.
- The circuit implementation is simple. We require only few components.
- A 12V DC supply is connected to the gate of the Mosfet through a push button switch.
- A LED is connected as our Load. We can connect other peripherals too.
- We are connecting a resistor R1 so that in a situation of zero gate supply there is no unwanted voltage at the gate terminal.
- The Push button helps us to connect and disconnect the gate supply.
Working of MOSFET SWITCH:
- When we push the Push button, the 12v supply gets connected to the gate terminal of the Mosfet.
- Therefore, the Mosfet gets ‘ON’ and it starts conducting. Hence the current starts flowing which makes the LED glow.
- In simple explanation, the LED gets connected to ground as Mosfet turns ON and it starts glowing. Its anode voltage will be 12V and cathode will be connected to the ground.
- Hence, in this condition the Mosfet works as a ON switch.
- Now we disable the Push button. Therefore, the 12V supply gets disconnected to the gate of the mosfet.
- The mosfet turns off.
- The led’s cathode terminal gets disconnected from the ground.
- Hence, it stops glowing.
- No current Id flows now.
This is how mosfet switch works.
Check out this video of How to use Mosfet as a switch which gives implementation of DC Motor in place of LED.
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