With NE555 making push-button delay section lamp circuit
Posted on Nov 10, 2015 9064
With NE555 making push-button delay section lamp circuit shown in Figure 3-5, the circuit from when base integrated circuits,
power supply and road relay control circuit of several components. Usually the key switch SB and normally open relay contacts kl unit open, so H is not bright lights, do not eliminate the entire circuit consumes energy. Turn on the lights when needed, just click the switch SB, H lamp immediately energized to emit light. Meanwhile 220V AC by the capacitor C1 buck, VDl ~ VD4 rectifier diodes, voltage regulator VD5 and filter capacitor C2, the output DC voltage of about 12V. In this case charging the capacitor C3 through the resistor R2, since the voltage across the capacitor can not change suddenly, so the base circuit A illustrates the value end of the 6 foot was high time base circuit is reset, its output 3 pin output low, the relay K was electric pull station, close contacts kl close the circuit self-locking, so in this case, although the switch SB tripped lamp H still remain alight. As the capacitor C3 charging constantly, triggering end timebase circuit A 2 foot level declining, when the supply voltage drops 1/3, flip the circuit is set , the output terminal 3 feet high output, relay K Loss electric release, contacts kl jump lift self-locking, the circuit returns to the original state before starting the lamp H goes out. At this time when the C3 charge stored in the base circuit through the internal resistance of the diode VD6 vent discharge, can prepare for the next turn on the lights for the delay. That time delay circuit H lamp lighting time depends only on the charge R2 and C3 is a constant electricity when asked, regardless of other factors, the power supply voltage. Illustrated using data every time pressing SB, lights about two to three minutes, For an extension of time can increase the R2 (or C3) values; on the contrary, reduced R2 (or C3) values.