Low power LED corridor solar light

The corridor lights made with high brightness leds, it shut down during the day, automatic light after dark. A year of power consumption is less than 2 degrees, the service life of up to 10 years.

circuit working principle of the corridor lights circuit as shown in the figure below. By the capacitance step-down circuit, rectifier circuit, LED light-emitting circuit and photoelectric control circuit and other parts.

220 v alternating current through the capacitor C1, R1 step-down current limit in A and B two points after about 15 v ac voltage, by VD1 ~ VD4. For rectification, get about 14 v dc voltage on C2 as high brightness leds VD5 ~ VD8 working voltage, the working current of the light emitting diode is about 14 ma. Due to the capacitor C1 is not active power consumption, the consumption of bleeder resistor power is negligible, thus the whole circuit of the power consumption of about 15 x 0. 014≈0- 2 ( W) 。

in order to further save energy and prolong the service life of high-brightness light-emitting diodes, circuit joined by photosensitive resistance R2, R3 resistance and triode VT1 of photoelectric control circuit, such as in the night of photosensitive resistance R2 value can reach more than 100 k, the C2 at the ends of the voltage by the R2, R3 after partial pressure provided to VT1 base dc bias voltage is small, VT1 cut-off, does not have any effect of light-emitting diode work; When during the day, as a result of the action of the photoelectric effect, under the R2 resistance can be reduced to 1 ok, then VT1 conduction and close to saturation, because through the current biggest can reach 15 ma C1, because of the shunt VTl, C2 on voltage can drop below 4 v.

because the working voltage of each light-emitting diodes (leds) to achieve more than 3 v to start work, four series will reach more than 12 v, so at this time the light emitting diode can't normal light.

so, after the VT1 diversion 'short circuit', why power consumption of the circuit can decrescent? This is because the capacitance step-down circuit under the condition of the output voltage is not too high can largely be regarded as a constant current source, its power consumption is proportional to the load resistance, after VT1 shunt made the voltage drop on the C2, equivalent to a load resistance is reduced, so power consumption is decreased. With A and B at the ends of the voltage drop to 5 v, for example, suppose the C2 by alternating current on 15 ma, at this time of the circuit power consumption is about 5 x is 0. 015≈0. The euro ( W) 。 So in the night light up an average of 12 hours a day, for example, power consumption is: (a year 0. 2×12+0. 08×12) ×365≈1. 2 ( kWh) , which is 1. 2 degrees.

components selection and installation in the C1 use 0. 22 mu 250 vac metallized polyester film capacitor. R2 using CDS photoresistance, models for GL4516, its light resistance ( 10Lux) For 5 ~ 1 ok Ω, resistance to 0. 6 m Ω, can also use other types of CDS photoresistance and diverge from as long as the appropriate adjustment when the parameters of R3 resistance can. VD5 ~ VD8 with rated current to 20 ma, high brightness white light leds. Other components parameters shown in the below.

corridor lights can use old energy-saving lamp assembly. Remove the original bulb, leaving holes just as light-emitting diodes (leds) out of the hole, because the hole is larger, can use cardboard in four small opening corresponding to the position of the light emitting diode as a substrate. Without having to make the circuit board assembly, available to the old circuit boards are assembled, leaving four rectifier diode, originally a 400 v electrolytic capacitor to be removed for 25 v 100 mu of electrolytic capacitors, dismantling the redundant components on printed circuit boards, the corridor lights on lap weld of the other components using the original solder joints. Open a hole in the upper portion of the circular shell as light hole of photosensitive resistance, facilitate the outside light on the photosensitive resistance.

installed, turning on the power supply in normal indoor light, if blocking photoresistor light hole lamp is lit, remove the rear light is put out, said lamp working condition is normal. Finally in the corridor of the lamp installation are using, if the light is a bit dark during the day when the lamp is lit, can be appropriately increase R3 resistance; On the other hand, if the dark night when the lamp is not lit, can be appropriately reduced, R3 resistance. Under normal circumstances is not need to debug. The corridor lights after light.

note: due to the whole circuit is in 220 v ac power directly, so please be careful about making and debugging.