Capacitors in AC Circuits

12 A capacitor opposes the flow of an AC current.

A. What is this opposition to the current flow called? _____
B. What is this similar to in DC circuits? _____
A. Reactance
B. Resistance

13 Just as with resistance, you determine reactance by using an equation.

A. What is the equation for reactance? _____
B. What does each symbol in the equation stand for? _____
C. How does the reactance of a capacitor change as the frequency of a signal increases? _____
A. equation
B. XC = the reactance of the capacitor in ohms.
f = the frequency of the signal in hertz.
C = the value of the capacitor in farads.
C. The reactance of a capacitor decreases as the frequency of the signal increases.

14 Assume the capacitance is 1 μF and the frequency is 1 kHz.


Find the capacitor's reactance. (Note: 1/(2π) = 0.159, approximately.) _____


f = 1 kHz = 103 Hz

C = 1 μF = 10−6 F



15 Now, perform these simple calculations. In each case, find XC1 (the capacitor's reactance at 1 kHz) and XC2 (the capacitor's reactance at the frequency specified in the question).


Find XC1 and XC2: ...

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