POWER UNIT OF ELECTRONIC COUNTER

摘要

PURPOSE:To prevent supply of the erroneous input signal to the electronic unit at the service interruption time and thus to avoid the malfunction of the counter by providing the power circuit for electronic unit supplying the input signal plus the voltage detection circuit which detects the output voltage of the power circuit to the main body circuit of the electronic counter. CONSTITUTION:The 2-series of rectifier circuits 231 and 232 plus constant voltage circuits 251 and 252 are connected to the secondary side of transformer 22 connected to AC power source AC, and the output voltage of circuit 252 is supplied to the counter main body. At the same time, the output voltage of circuit 251 is applied to electronic unit 26 applying the input signal to the counter main body as well as to voltage detection circuit 29 which detects the output voltage of circuit 251 at the service interruption time. And when the output voltage lowers less than the fixed level due to circuit 29 at the service interruption time, the detection signal is sent to the counter main body through the photo coupler consisting of light emitting diode 292 and photo transistor 32. Thus the signal input function is stopped to the counter main body to prevent occurrence of the malfunction.