2023. 12. 24. 22:41ㆍTechnology
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Is there such thing as a normally closed MOSFET?
Is there such thing as a normally closed MOSFET? Or can I somehow make a circuit?
Can I control a circuit that functions like that with a control logic voltage of 3.3 V or 5 V so that when I give a logical high the normally closed circuit changes to open?
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2 Answers
Depletion-mode MOSFETs conduct with zero Vgs.
N-channel devices are easily available and useful in some specialty applications such as loop-powered instrumentation. You apply a negative Vgs to turn them off, like the grid on a vacuum tube.
P-channel devices (with the possible exception of RF devices) are unavailable or close to unavailable, afaik.
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Yes, they are called depletion mode devices and they are harder to find.
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Is there such thing as a normally closed MOSFET?
Is there such thing as a normally closed MOSFET? Or can I somehow make a circuit?
Can I control a circuit that functions like that with a control logic voltage of 3.3 V or 5 V so that when I give a logical high the normally closed circuit changes to open?
1276 bronze badges
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Depletion-mode MOSFETs conduct with zero Vgs.
N-channel devices are easily available and useful in some specialty applications such as loop-powered instrumentation. You apply a negative Vgs to turn them off, like the grid on a vacuum tube.
P-channel devices (with the possible exception of RF devices) are unavailable or close to unavailable, afaik.
386k21 gold badges332 silver badges869 bronze badges
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