Electronic time switch e.g. for control of lighting in stairwell and entrance halls

摘要

The electronic time switch uses a circuit incorporating a triac switched in series with the load resistor. A gate is joined to the resistor and to a diac and from this a capacitor goes to the triac anode. A rectifier in the alternating voltage circuit and a field effect transistor govern a phase-cutter. The capacitor-resistor-diodes coupling used in this circuit functions as a time link. The gate receives only positive voltage, so that the field effect transistor is controlled. The parallel gate-source-resistor acts as a discharge resistor for the capacitor. The system can be used as an electronic time switch, gradually switching off lights and reducing energy consumption.