Using a P-channel MOSFET as in Normally Close Circuit
The ZVP2110a is an P-channel Power Enhancement mode MOSFET. Having made a Normally Open circuit previously using an N-channel MOSFET, I thought why not create a Normally Closed circuit using an P-channel MOSFET. When gate-to-source voltage at -10V (source voltage greater than gate voltage), the MOSET turns ON and the LED lights up. When a control signal is applied to bring gate-to-source voltage to 0V or greater, the MOSFET turns off, in turn switching the LED off.
The table below which I took reference from here, does a nice of explaining the different modes of operation for the different types of MOSFETS.
Happy Hacking!
MOSFET Type | V GS << 0 | V GS = 0 | V GS >> 0 |
---|---|---|---|
N-channel Enhancement | OFF | OFF | ON |
N-channel Depletion | OFF | ON | ON |
P-channel Enhancement | ON | OFF | OFF |
P-channel Depletion | ON | ON | OFF |