Vds was given in DC steady state as VDSdc = 4.9V and about the gate current.. Can it be associated with isolated gate and hence Ig=0 in steady state?Were you given Vds? If not, how did you calculate it?
Assuming your Vds is correct, then your answer is close, but there is a small error from rounding: Vds + Vr2 = Vdd = Vgs (after sufficient time for the gate capacitance to charge and assuming no gate leakage, i.e., no gate current).
John
I did not see that value in the question you posted. With many mosfets at a gate Vgs of 7V, one might expect a lower Vds, but the value you used is not unrealistic.Vds was given in DC steady state as VDSdc = 4.9V and about the gate current.
Yes, to a first approximation. Look up a datasheet for a mosfet that you have available. In my case, I have an IRF1010E. At 20V Vgs, gate leakage is specifed as 100nA. That is very small, but your gate resistor is 0.25M, which is large for a gate resistor. Therefore, VR1 would be 0.1*0.25= 0.025V with a Vgs of 20 V. Now, your Vgs is less and your mosfet isn't specified, so I assume it is "ideal" and has no gate leakage.Can it be associated with isolated gate and hence Ig=0 in steady state?
so assuming that it is ideal,is the equation for Vgs correct?I did not see that value in the question you posted. With many mosfets at a gate Vgs of 7V, one might expect a lower Vds, but the value you used is not unrealistic.
Yes, to a first approximation. Look up a datasheet for a mosfet that you have available. In my case, I have an IRF1010E. At 20V Vgs, gate leakage is specifed as 100nA. That is very small, but your gate resistor is 0.25M, which is large for a gate resistor. Therefore, VR1 would be 0.1*0.25= 0.025V with a Vgs of 20 V. Now, your Vgs is less and your mosfet isn't specified, so I assume it is "ideal" and has no gate leakage.
Regards, John
The gate is basically a capacitance - for any effect you can measure, its resistance is pretty much infinite.Hi I don't know how to identify gate-source voltage in this example: View attachment 90906
Can anybody help?
by Duane Benson
by Jake Hertz
by Jake Hertz