Question

HOW DO YOU DO THIS?

What is the peak voltage on a capacitor if the RMS voltage of a sinusoidal waveform signal across it is 10.00 VAC? Please make sure to explain the answer.

Answer 1

Let us start by explanation of some basic concepts about a capacitor connected to a sinusoidal voltage source . Like we have resistance when we deal with ac we define impedence. For capacitance it is called capacitive reactance. which is given by

where C is capacitance , is the angular frequency of the source voltage. . 'f ' is the frequency of voltage.You might have seen 50Hz source, 60 Hz source.. That is the frequency of voltage supplied by source..

So like we deal with resistances we deal with reactances. This brings a kind of uniformity and makes things easier for us.

Consider a circuit with a sinusoidal voltage source connected to a capacitor. Instantaneous voltage of voltage source is given as.

V_m is called peak voltage of source. We define another voltage parameter known as rms voltage. The relation between rms and peak is.

.

If I is the magnitute of current flowing in the circuit. Then peak voltage across capacitor is given by.

.

.

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For the given problem we have

.

Therefore  

Or peak voltage across capacitor is