In the context of A.C. (alternating current) fundamentals, "Vc" typically refers to the voltage across a capacitor in an AC circuit. The behavior of a capacitor in an AC circuit varies with the frequency of the AC signal.
A capacitor's impedance (AC resistance) is given by the formula:
Zc = 1 / (2 * π * f * C),
where:
Zc is the impedance of the capacitor,
π is the mathematical constant pi (approximately 3.14159),
f is the frequency of the AC signal, and
C is the capacitance of the capacitor.
The maximum voltage across the capacitor (Vc) will occur at a frequency where the impedance of the capacitor is at its minimum. In other words, the impedance is inversely proportional to the frequency. As the frequency increases, the impedance decreases, allowing more current to flow through the capacitor, which leads to a higher voltage drop across it.
Therefore, the frequency at which Vc (voltage across the capacitor) is maximum corresponds to the frequency at which the impedance of the capacitor is minimized. This frequency can be calculated using the formula for impedance provided earlier. The value of C (capacitance) is a constant for a given capacitor, so adjusting the frequency f will determine the point at which Vc is maximized.
In summary, the frequency at which Vc is maximum in an AC circuit is the frequency that results in the minimum impedance for the capacitor based on the formula Zc = 1 / (2 * π * f * C).