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How to use LED to improve the power of the flashlight

From: Data:10/08/2016

describes the power supply to the voltage from a section of the flashlight battery to 3.5 volts to LED required 1.5 volts, while the power to LED and flashlight batteries in series up. The design of this circuit is to use LED to improve the flashlight.

booster circuit in a battery of two batteries will be replaced by a section of the battery, LED device instead of incandescent lamp (see Figure 1).

result is, only with a flashlight battery, LED flashlight can be used for a long time. The design of the biggest difficulty is: when the power supply is only one end connected to the battery and the other end connected with the incandescent lamp, improve the voltage.

Figure 2 shows the power circuit to rely on a trick to work. In the LED device, a diode connected to the LED is connected to the power supply to absorb the current, and the current is passed through the diode. During this period, the LED is reverse biased. After a short period of time, the power supply stops absorbing the current and turns to the power supply, so that the LED is in a state of positive bias.

1: booster circuit in two batteries of the flashlight will replace the battery, LED device substitutes incandescent

Figure 2: power supply circuit depends on a trick to work

“ part & rdquo; is a blocking oscillator, the oscillator using two transistors instead of the usual one transistor. When the transistor is electrically conductive, one end of the inductor is connected with the power source, and the other end of the inductor is connected with the power supply side by the NPN transistor. The current has been accumulated in the inductor until a transistor is saturated. The base voltage is turned over so that the two transistors are quickly cut off.

when the two transistor cutoff, as well as the inductor coil voltage along with the current through the inductor and reverse, the inductor through the diode D1 and D2 release current. As a result, one end of the positive electrode is connected with the negative electrode of the battery by D2 at one end of the cathode. In addition, one end of the negative electrode is connected with the positive electrode of the battery through the D1. When the circuit oscillation, the inductance is constantly changing in these two conditions (current through the transistor accumulation and the release of D1 and D2). The resistance of

4.7 can be paralleled with the LED and slightly reduced the turn-on voltage. In the original design, the turn-on voltage was reduced from about 1.3 volts to less than 1.1 volts. This is very meaningful, because a new section of the basic flashlight battery discharge to 1.1 volts is likely to be the time required to discharge to 1.3 volts two times the time required.

and 2N4401 connected to the 100 thousand ohm resistor is used to ensure that there is enough leakage current to make the transistor conduction, so as to start the oscillator. Inductance is continuous No. 32 single strand magnetic metal line in ferrite soft magnetic materials TC8.2/3.7/4-3E7 ring core around 45 turns into. The 15 and 30 turns are provided with a tap, which constitutes the three part of each part of the 15 turn. Oscillation frequency at 1.6 V battery voltage is 17kHz.