Daylight actuated light switch control circuit - has triac and delay device between two comparators, with one comparator connected to switch at other comparator

摘要

The lighting control circuit for e.g. an office is designed to operate under different lighting conditions but includes a delay so that the lights are not switched off and on too frequently on e.g. a cloudy day. A comparator (K1) is preceded by a junction (1) to which actual value and nominal value voltages are applied. This gives a positive output when the actual value is greater than the nominal value. This is followed by two resistances (R3, R4) and a capacitor (C1) forming a delay device. The delay device is connected to a second comparator (K2) followed by a trial stage (TR). The output of the second comparator is also connected by a second line (2) to a switch (S1) which operates hysteresis dependent on the of the two coupling resistances (R1, R2) at the input of the first comparator. A diode (D1) is in parallel with the second resistance (R4) of the delay device so that negative signals pass through without delay.