Found this: What is the direction of current flow in P channel MOSFET? [image: Simple MOSFET Switching Circuit – How to turn on / turn off N ...] Current flows into the drain and out of the source. P-channel MOSFETs turn on when the gate is a few volts below the source, and the drain-source voltage is negative. Current flows into the source and out of the drain.
In a P-channel MOSFET, the source is connected to a positive voltage, and the FET will turn on when the voltage on the gate is below the source voltage by a certain amount (Vgs < 0). On Thu, Jul 13, 2023 at 1:58 PM Chuck McCown via AF <af@af.afmug.com> wrote: > For the first time ever, I needed a high side solenoid coil driver. > > So reading up on high side drivers, I felt confident. P channel mosfet > etc. > Does not work. > > Come to find out that the *source* of a P channel mosfet is supposed to > be connected to the positive supply. > > Source = source of electrons Negative, ground, right? > Drain = drain for electrons.... right... positive, does this not > reference electron flow? > > Source must mean hole source for P channel mosfet. > ??????????????????????????? > > Arrgh.... Now gotta kludge circuit boards to test but really will have > to scrap the lot. > > I thought the schematic looked odd because it put the internal body/free > wheel in conduction mode when the transistor should be off. > AND I found reference schematics showing it with Drain positive... I > figured others have drawn schematics of this exact transistor with Drain > positive, surely those schematics are not erroneous. They are published on > the interwebs for heck sake.... > > Ennybuddy know enough solid state device physics to be able to tell me > what Source actually means for a P channel mosfet? > > > Best Regards, > Chuck McCown > > McCown Technology Corporation > 8401 N Commerce Dr > Lake Point, Utah 84074 > 801-250-9503 Office > 435-830-4306 Cell > www.mccowntech.com > www.microtrench.pro > www.terabitnetworks.com > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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