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MOS gate retention characteristics question

jv1597

New Member
I have a question on how a MOSFET reacts to multiple subsequent input at the gate. I'm working on a simple supply circuit consisting of two MOSFETs, a first MOSFET for current-limiting supply to a second MOSFET but I'm without equipment to try it out on-hand at this time. I would like to know if a subsequent input value of .5v at the gate on a MOSFET would be cumulatively retained after a prior input of .5v, summing both input values to 1v altogether; and if so, I would also like to know how accurately a value is retained and for how long. Thanks.
 

Papabravo

Well-Known Member
A MOSFET gate looks like a capacitor that must be charged and discharged. The memory, if you can call it that, disappears quite rapidly in relative terms. It is similar to a series RC circuit where the voltage rises and falls exponentially with a time constant τ. As a rule of thumb, it takes about 5 time constants to reach 99% of the final value. I would not expect any "summing" action on MOSFET gates.

That said, a schematic diagram of what you have in mind is worth more than several paragraphs of verbiage and maybe I don't understand what you are describing.
 

jv1597

New Member
Here is a depiction that might help...

Drawing 1.jpg
 

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