Problem with MOSFET in my circuit

[madhu.b]

Hi,


I have problem with Mosfet in my circuit. I have input supply voltage of 120V for the circuit and voltage of 12v for the gate driver.

when I am supplying +12v to the gate of the Mosfet. Drain is not supplied by input voltage of 120V.

when I am not suppliying 12V to Mosfet gate(when the gate driver is off),then the drain is supplied by 120V.


Do you think the Mosfet is not working??. I cannot figure out the problem.


Can anyone suggest me something about this.


Regards
madhu

 

[Tahmid]

The MOSFET acts as a switch. So, when it is on, you can think of it being a short between drain and source. You will get 120V across the load and 0V across the MOSFET (ideally). That's why you don't measure 120V at the drain. Instead, when the MOSFET is off, the voltage reading at drain with respect to source, will be 120V, since drain is not shorted to source then.

Hope this helps.
Tahmid.

 

[picgak]

when I am not suppliying 12V to Mosfet gate(when the gate driver is off),then the drain is supplied by 120V.

Regards
madhu

It is normal to have +120V accross mosfet when it is in off condition