What is this Mosfet circuit used for ?

[Vulture]

Hi guys,

Got a question:

Refering to the circuit attached:

1) What is the circuit used for?
2) Should Mosfet A be a P-mosfet or a n-mosfet?

Rgds

 

[keith1200rs]

Mosfet Circuits

With a PMOS it could be used to switch a high voltage, high current with a logic level signal.

Keith

 

[Tahmid]

Mosfet Circuits

As keith said, the circuit is intended switch a high voltage, high current with a logic level signal. But, I see one problem here, that there is no level shifting, which would damage the P-channel MOSFET as max voltage between gate and source is 20V. Here the difference becomes 40V, so add a 30V zener in the collector path for level shifting.

Hope this helps.
Tahmid.

 

[frankliner]

Mosfet Circuits

VGS is limited by the resistive divider. You don't need a zener.