Ammeter connected in an AC circuit measures______________?
Correct answer: B. RMS value of the current
- A. The exact value of the current
- B. RMS value of the current
- C. The net value of the current
- D. The peak value of the current
Explanation
A standard AC ammeter is calibrated to indicate the RMS value of alternating current, which produces the same heating effect as an equivalent DC current. RMS current is measured in amperes and equals Ipeak/√2 for a sinusoidal current. Students may choose d because the peak value is the maximum instantaneous current, but an ordinary AC ammeter does not normally display that maximum.
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About AC Through Resistor, Capacitor and Inductor
Alternating current through a resistor, capacitor and inductor involves phase relationships between voltage and current, reactance, impedance and energy transfer. A resistor keeps voltage and current in phase, while a capacitor and inductor produce opposite phase shifts, a distinction used in circuit diagrams and numerical calculations.
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