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How does a MOSFET gate behave like a capacitor?
In the case of the mosfet, once you apply a voltage to its gate, it stays that way until you remove it. You could say that the nfet’s base behaves like a resistor, while the mosfet’s gate behaves like a capacitor.
How are gate capacitances of a MOS calculated?
I have read somewhere that the gate capacitance (Cgs, Cgd) of a MOS is calculated as below: where Cov is overlap capacitance. Could anyone explain where do the formulas come from? I couldn’t find a link that explains that now. Reading in the tea leaves here, I’d surmise that for the case of:
How is the capacitance of a gate oxide channel calculated?
Now taking as an approximation, the GATE-OXIDE-CHANNEL form a capacitor with capacitance C g = C o x. W. L, if you look at the channel at different regions of operation you can easily derive the approximations. you could assume C g d = 0 to simplify your calculations.
How is a nFET different from a MOSFET?
Click to expand… The difference between an ordinary nfet and a mosfet is that the former works by applying a current that flows through the base, while the latter works by applying a voltage to its gate. That is, you need current in order to get the nfet started, and to keep it going.
What kind of MOSFET is used in high side switch?
The MOSFET used in the this high side switch is a logic level 4P03L04 from Infineon and as it only needs its gate to be 4.5V lower than the 12V supply, the 12Vpp waveform applied to its gate easily switches the MOSFET on or off.
Can a PWM be applied to a MOSFET gate?
If you want to PWM the LED brightness then you would apply the PWM digital signal directly to the MOSFET gate so that the MOSFET is operating in the high efficiency switch-mode. Yes, by all means do remove C14, it serves no practical purpose.
Can a MOSFET be used on a low voltage circuit?
Whilst this may not be a problem at low voltages, MOSFETs can be used to switch high voltage circuits where having a high voltage present on an apparently inactive circuit can be a safety problem by creating a shock hazard.