Flashing warning light produced by light control NE555 circuit

  
VDI, VD2, C3, C4 compose a simple half-wave rectifier capacitor step-down regulator circuit. After power across C3 can output 12V DC voltage of about, for the time base circuit electricity.
Flashing warning light produced by light control NE555 circuit - schematic

A time base circuit and RP1, RP2. CI, RG to form a light-controlled self- excited multivibrator, exposed to bright light during the day RG showed low resistance, time-based circuit 4 foot level is less than 0.4V, A is forced to reset, constant output pin 3 is low and a half, vs no trigger is in the off-state voltage, lamp H does not shine. No light shines at night RG shot showed high resistance, so that it RP2 partial pressure of 4 feet level when the base circuit is increased, and is greater than 0.4V. Thereby lifting the timebase circuit blockade began start-up circuit. Start-up principle is: Let A 2 feet low, then A is set, 3-pin output high. CI = I foot the capacitor is charged by RP1, so that the voltage across CI namely A sixth foot level rise, when the supply voltage rose 2/3, A reset, 3 pin output low, then C1 3 feet by RPI to discharge, CI namely a voltage across the second leg level declining, when the power supply voltage is reduced to 1/3. A mutation has been set, 3 feet high level, but also to the CI by charging ...... RP1, an oscillation cycle. The output gap nozzle 3 feet high and low level, when the 3-pin output high, vs can be obtained and opened by Rl trigger current, H lamp is lit: When the 3-pin output low, vs loss of trigger current in the AC zero crossing that is turned off, the lamp H goes out. From the above analysis it shows that, with the time-base oscillation of electric prostrate, warning lights flashing H will continue to emit light. Potentiometer RPI is used to adjust the frequency of blinking lights of H, RP2 is used to adjust the sensitivity of the light control circuit, the circuit can work under appropriate illumination. The incandescent H circuit is working half-wave voltage condition, although flashing light, but life is quite long.




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