What is the maximum instantaneous value of an alternating voltage or current measured in either positive or negative direction?

• A. Arc
• B. Bridge circuit
• C. Amplifier
• D. Amplitude

Answer: (D)

The maximum instantaneous value is the peak value, or amplitude, of an AC waveform. When voltage or current varies sinusoidally, it can reach a highest positive value and a lowest negative value. The amplitude is the magnitude of that peak, i.e., the largest value the waveform attains in either direction, measured in volts or amperes. The peak-to-peak value would be twice this amount, representing the total swing from the positive peak to the negative peak. The other terms describe different ideas: an arc is a discharge path, a bridge circuit is a specific circuit arrangement, and an amplifier is a device that boosts signal strength.