In a mosfet power amplifier, using multiple-parallel mosfets, what's the surest way to check in an otherwise working amp that you haven't got the odd one gone o/c?
They usually fail short if that helps! With the amp playing a 50Hz tone, if you can measure any AC voltage across the source resistor then the FET is conducting OK. Compare with readings across the other resistors to improve confidence.
They don't always fail short; if they do, the amp is no longer a 'working' one!
Many designs of power amp dont use source resistors, they're all parallelled with individual gate resistors.
Many designs of power amp dont use source resistors, they're all parallelled with individual gate resistors.
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