High Brightness LED Flashlight

Do you know the principle of high brightness LED flashlight? Let me show you. Put through power supply, power through the L1b and R to provide VT on the base current, VT began to conduction, collector current increases. VT gradually saturated conductivity. Then L2 sensing the voltage, but the voltage polarity is negative, VD can't conductivity, the power supply energy into electromagnetic energy, stored in pulse transformer T: VT saturated, because the current in the inductance can't mutations, making drop, "a higher on L2 under the voltage is negative, this time VD conduction, charging to C, and lit LED, inductive energy and transformation for electric power supply load (LED). VT is equivalent to a switch, T is the energy storage components, VT conduction and globe alternately, low voltage dc power was booster become high voltage. This is the work principle of dc converter.

 A circuit, pulse transformer is the key element. With high magnetic permeability surround system, this is a kind of power ferrite, which have to adapt to the characteristics of high frequency power. It comes from old energy-saving lamps electronic ballast or old computer on the main board. They are generally high permeability, which can meet the requirements. Appropriate chooses bigger. L1 use normal single strands of insulation wire around 10 turns, in 6 in turns tap, will L1 into L1a (6 circle) and L1b (4 turns) two section, with the same wire around the L2 10 to 12 circle, a single strand insulation wire around if not good, also can use high strength enameled wire around the system.

 VT choose electronic ballast of commonly used three DD13003 or MJE13003, request HFE quartile 20, 100 O ordinary gold R choose the membrane resistance. VD choose IN4148 switch tube, if use FR107 emission of high frequency that is better. LED choose 8 mm to 10 mm in diameter of LED, if use ordinary 5 mm LED, which can use 2 ~ 3 only used in parallel, want to choose a performance parameters consistency good LED tube, in case the brightness not uniform.

 Due to the circuit is simple, use little component, so don't have to use printed circuit board. Use direct components lap, also can use knife carved out a small piece of printed circuit board, installed in the flashlight.

 This circuit can also be used for the 1.5 v power supply of teaching with laser emitter (electronic pointer) and the functionalities of some LED small desk lamp. If this circuit uses more, they can increase L1 and L2's circle number, improve the L1 and L2 than circle number, VT DD13005 etc to three more power tube, VD and C for higher compression, the power supply voltage up to 9 v ~ 12 v, the improved LED flashlight circuit can be used as a simple dc high voltage generator.