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Earth referenced bias into floating circuit?

  1. Aug 1, 2016 #1
    What happens if I for example, connect an earth referenced bias voltage to the gate/grid/input of a mosfet/tube/opamp that uses a floating power supply?
    Does the bias simply not work or does the circuit somehow become earth referenced?
  2. jcsd
  3. Aug 1, 2016 #2


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    I suspect you know the answer to this. There always has to be a return of some kind. It is likely you would introduce a lot of hum. It would not bias in a useable or constructive way.
  4. Aug 11, 2016 #3


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    In the case of FETs you will get some really confusing results. If you happen to luck out and get all of the voltages correct you will not have current paths to charge and discharge the gate capacitance properly. Shenanigans will ensue.

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