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basic mosfet question

hello,

I was wondering how much voltage should we measure in the gate of a P-channel power MOSFET. I ask this because I am trying to repair a Philips monitor. I found out that the B+ going to the collector of HOT connected on the drain of a power MOSFET (IRF 9620). The low voltage power supply works fine. I can measure dc voltage on the source terminal of the MOSFET but there is no voltage present on the drain. So there is no HOT collector voltage. Now measure the gate dc voltage and the dc gate voltage I think is too high (same voltage as with the source). Gate is connected through a crystal diode and a 22k resistor. Are these passive components do not provide any voltage drop to the gate? Can anyone give me some explanation about this and how P-channel mosfet works in general. Also what is gate drive?

thanks in advance for explanation and patience.

ian

Reply to
cheian07
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HOT ?????

Graham

Reply to
Eeyore

Think real hard about it. A collector, B+ and a monitor.

Horizontal Output Transistor

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Member of DAV #85.

Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

Hi, Ian. Try sci.electronics.repair , and be sure to include the model number of the monitor.

I'm sure you'll get a bit of good advice there.

Good luck Chris

Reply to
Chris

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