Using MOSFET as a switch and controlling with a microcontroller

Using N-Type MOSFET as a switch in a LED circuit to control the LED. The power source is set to simulate a microcontroller turning on and off one of its pin to 3V and 0V in 10ms intervals. When the voltage source turns on for 10 ms the 3V is sent to the N-Type MOSFET, when the MOSFET gate reaches saturation and MOSFET activates, the current passes through source and drain completing the circuit and switching on the LED. The resistor in parallel to gate and drain makes sure the voltage goes to ground when logic voltage (input voltage that is activating mosfet 3V) is weak or disconnected. If this resistor does not exist, the LED will remain always in an on state when the voltage to the gate is disconnected. Play around with location of Resistor to understand the concept, we can also add another resister in series after the parallel resistor that will limit the current to the gate during switching. Also when the series resistor is connected but the parallel resistor is absent and when logic voltage disconnects the the LED will always remain on.

published 1 year ago