| 摘要 |
PURPOSE:To ensure the correct input of an AC signal even without using a smoothing circuit by feeding the AC input signal to a voltage detecting circuit only when the instant value of the AC input signal is set at the maximum level. CONSTITUTION:The output of an AC signal power supply 1 is supplied to an input terminal 7a of a voltage detecting circuit 7 via voltage dividing resistances 3 and 4 after undergoing the full wave rectification through a rectifying diode 2. While the output of a diode-stat 2 is supplied to a delay pulse generating circuit 9 which generates pulses with a time delay of 1/4 cycle of the power supply 1 via a zero voltage detecting circuit 8. The maximum value (crest value) of an input signal is detected from the circuit 9 and then applied to an input terminal 7b of the circuit 7 as an input timing signal. The circuit 7 accepts the input from the terminal 7a only when the output signal of the circuit 9 is delivered. Thus the AC signal can be fed correctly even without using a smoothing circuit. |
