Electrical system design in to solar side and load side
Posts
1 WATT LED very good design
Circuit takes 70mA on LOW brightness and 120mA on HIGH Brightness This circuit has been specially designed for a 6v rechargeable battery or 5 x 1.2v NiCad cells. Do not use any other voltage. It has many features: The pulse-operation to the two 1-watt LEDs delivers a high current for a short period of time and this improves the brightness. The circuit can drive two 1-watt LEDs with extremely good brightness and this makes it more efficient than any other design. The circuit is a two-transistor high-frequency oscillator and it works like this: The BD139 is turned ON via the base, through the white LED and two signal diodes and it amplifies this current to appear though the collector-emitter circuit. This current flows though the 1-watt LED to turn it ON and also through the 30-turn winding of the inductor. At the same time the current through the 10R creates a voltage-drop and when this voltage rises to 0.65v, the BC547 transistor starts to turn ON. This robs the base of the B...