Hey guys,

Amazing to be in this group ! Please find attached the diagram of the problem. Please find attached or via the link the wiring scheme.

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E = 10kV at 60Hz, C1 = 60pF and R1 = 1k.

I have to compute the ac voltage in reference to ground at point [1]. Does it means that I need to compute the voltage at the resistance or the capacitor ? I was thinking it's the the voltage drop between the ground and the resistance, so here is my solution :

Vr(w) = R1/(ZC1(w) + R) * E(w) = 1/(1+jR1C1w)*E(w).

Then I have to compute the cut off frequency, as this is a RC classical scheme,fc = 1(2*π*R*C) right ?

Thanks for the help !

 

Pretty hard to determine the AC voltage at point [1] when the diagram doesn't indicate which point is point [1]. Fortunately the only point that makes sense is the node marked 'PD'.

Voltage is not measured "at" a point, it is ALWAYS a voltage differential BETWEEN (or across) two points. The question asks for the voltage at point [1] (which I'm assuming is the 'PD' node) in reference to ground -- that means the voltage difference between point [1] and the ground node which, in turn, means the voltage ACROSS the resistor.

 

WBahn, thanks for you answer !

Here are the point

 

Hint: imagine the capacitor was replaced by a resistor of 2kΩ, you could ‘compute’ the voltage across R1 by finding the current flowing through the two resistors and multiplying it by R1.

The cut off frequency is normally considered as the point of ½ power transfer (or 3dB) in electronic circuits; where the full voltage Vin is reduced to 0.707Vin.