The effective value of ac voltage or current is（ ）
A: The average value of a voltage or current
B: DC equal to the AC thermal effect is defined as the effective value of AC
C: voltage or current are 0.707 of their amplitudes
D: closely related to the frequency of alternating current
A: The average value of a voltage or current
B: DC equal to the AC thermal effect is defined as the effective value of AC
C: voltage or current are 0.707 of their amplitudes
D: closely related to the frequency of alternating current
举一反三
- The function of direct current regulated power supply is to input an alternating current power of 220volts, so that it can output __________.( ) A: alternating current 200 volts voltage B: direct current 24 volts voltage C: direct current 200 volts voltage D: alternating current 24 volts voltage
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