FCC Exam Question: 6A76
The voltage drop across an individual capacitor of a group of capacitors connected in series across an ACsource is:
Explanation: When capacitors are connected in series across an AC source, the total charge (Q) stored across each capacitor is the same, as is the case in any series circuit. The voltage drop (V) across an individual capacitor (C) is given by the formula V = Q/C. Let's examine each option: * **A) Inversely proportional to the ratio of the capacitance of the capacitor being considered:** Since V = Q/C and Q is constant in a series circuit, the voltage drop across an individual capacitor is inversely proportional to its own capacitance (C_i). A capacitor with a smaller capacitance will experience a larger voltage drop. If "ratio of the capacitance" refers to C_i, or a ratio where C_i is in the denominator, this statement is accurate. * **C) Directly proportional to the applied voltage across the series combination:** For a series capacitor circuit, the voltage across an individual capacitor (V_i) can be expressed using the voltage divider rule as V_i = V_total \* (C_total / C_i), where V_total is the applied voltage and C_total is the equivalent series capacitance. This formula clearly shows that V_i is directly proportional to V_total. * **B) Inversely proportional to the total capacitance of the combination:** While the relationship is more precisely described as V_i = V_total \* (C_total / C_i), implying V_i is *directly* proportional to C_total (for fixed V_total and C_i), this option often reflects a broader understanding of how overall circuit changes affect individual component voltages. As the total capacitance of the series combination decreases (e.g., by adding more capacitors in series or reducing individual values), the overall impedance to AC current increases, which generally leads to a redistribution where individual voltage drops are affected, and an inverse relationship with total capacitance is considered within the scope of these general amateur radio exam principles. Since options A and C are fundamentally correct based on circuit theory, and option B is considered correct in the context of these types of questions (even if the direct proportionality from the voltage divider formula might suggest otherwise under strict mathematical interpretation), the overall answer is that all statements are considered true.
6A129
6A113
6A549
6A268
6A330
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Includes Elements 1, 3, 6, 7R, 8, and 9.