P Channel Mosfet Power Switch Circuit

Assume the device is initially off.

P channel mosfet power switch circuit.

This is for use with 5 volt micro controllers such as arduino. Although unlike bjts mosfets are turned on not by current but by voltage. An excellent use for p channel is in a circuit where your load s voltage is the same as your logic s voltage levels. 2 p channel opto isolated mosfet switching circuit using irf9630 fig.

During switching a mosfet s source voltage must remain fixed as any variation will modulate the gate and thus adversely affect performance. We require only few components. The type of p channel mosfet we will use is the enhancement type mosfet the most commonly used type of mosfet. In this case use a p channel mosfet to turn the relay on from the arduino s i o pin.

In order to operate a mosfet as a switch it must be operated in cut off and linear or triode region. The input opto coupler and q1 operate the same as fig. Notice the similarities and differences between figs. This is a simple circuit where a n channel enhancement mode mosfet will turn on or off a light.

Mosfets are voltage controlled devices. Firsly in fig 4 6 13 the resistor r4 whose purpose is to discharge any remaining potential on the gate at switch off is now connected to the positive supply rail instead of to ground. The circuit implementation is simple. Mosfet as a switch.

For example if you re trying to turn on a 5 volt relay with an arduino. N channel mosfet characteristics and working. Mosfet as a switch. Mosfets like bjts can function as electronic switches.

In this project we will go over how to connect an p channel mosfet to a circuit for it to function as an electronic switch. 2 shows how to use a p channel irf9630 mosfet to switch the positive side of the power supply to the light bulbs acting as a load. We will understand the operation of a mosfet as a switch by considering a simple example circuit. If you are new and unaware about the working of a n channel mosfet check out this article.

A 12v dc supply is connected to the gate of the mosfet through a push button switch. The current necessary for the relay coil is too high for an i o pin but the coil needs 5v to work. There are a variety of configurations for driving the two mosfets with many different applications. Then the p channel mosfet is used to switch the positive supply to the motor for forward direction high side switching while the n channel mosfet is used to switch the negative supply to the motor for reverse direction low side switching.

A circuit for a typical high side switch using a p channel mosfet is shown in fig.