How to use mosfet as a switch?

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asad parvez

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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
 

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.
 
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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
 

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??
 

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.
 

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