Control circuit for intermittent drive windscreen wipers - has reverse coupled quenching loop for transistor driven relay

摘要

The windscreen wiper intermittent drive control circuit has a transistorised switch in line with a control relay to provide direct control of the relay and to prevent relay points bounce. The basis of the transistor is linked to a quenching loop to prevent bounce when switching. The emitter of the transistor is linked to the timing control which provides the sweep pulses. The quenching loop has a low resistance coupling to the emitter and to the other pole of the supply.