How to use mosfet as a switch?

[asad parvez]

Can any1 tel me how a mosfet can b used as a switch?

In what way it should be connected in the circuit and which mosfet is ideal for switching purpose for my small projects or is there any option other than a mosfet which is better to use as a switch please help

 

[tpetar]

MOSFET as a Switch
https://www.electronics-tutorials.ws/transistor/tran_7.html

Examples:
https://www.google.rs/search?q=mosf...3L4nZsgbDzoDwAg&ved=0CCoQsAQ&biw=1024&bih=608

**broken link removed**

The gate input voltage VGS is taken to an appropriate positive voltage level to turn the device and therefore the lamp either fully "ON", ( VGS = +ve ) or at a zero voltage level that turns the device fully "OFF", ( VGS = 0 ).

If the resistive load of the lamp was to be replaced by an inductive load such as a coil, solenoid or relay a "flywheel diode" would be required in parallel with the load to protect the MOSFET from any self generated back-emf.

 

[Shady Ahmed]

Can any1 tel me how a mosfet can b used as a switch?

In what way it should be connected in the circuit and which mosfet is ideal for switching purpose for my small projects or is there any option other than a mosfet which is better to use as a switch please help

The input is connected to the "source" terminal of the MOSFET . The output is connected to the 'Drain' & the control is connected to the gate..

But also , slight changes may occur depending on the input u want ...

I mean if connect the input to 'High' voltage , then u need PMOS .. and the switch is inverted ... tell me if u didn't get what i mean ..

and if the input 'changes' (sometimes it is high and sometimes low) ,, u have to use both .,, PMOS & NMOS in parallel

 

[asad parvez]

What are the design equations of Rn and Rgs?

So that the device will not be damaged??

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What are the design equations of Rn and Rgs?

So that the device will not be damaged??

 

[elecbaba]

Gate voltage should not exceed the recommended maximum voltage in datasheet. 10K is typical for Rgs. Rn can be of value from more than a few ohms to several KOhms. Less is for high frequency.