Input circuit for monitoring signals e.g. for approximation initiators has discharge circuit connected between AC input terminals connected to power supply line

摘要

Input circuits (21,22) are connected to AC input terminals (17,18) connected to power supply line (L1) via switches. A discharge circuit (23) is connected between the AC input terminals. The discharge resistance (RC) is less than input resistance (Re). The discharge circuit has a series circuit of rectifier (d), discharge resistance (Re) and transistor (S3).