vividvilla
Junior Member level 3

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The idea for this circuit came when I was repairing my aunt’s emergency light. Bulb based emergency lighting has a low efficiency and ultrabright l.e.d.s provide greater efficiency and more illumination, with a much extended battery life. It was therefore decided to change from a 12V light bulb to a pack of l.e.d.s. To get constant light, a constant voltage technique was adopted, using the circuit in Fig.2. For more power saving, step-down switching is used in preference to step-up. This function is provided by IC1 in conjunction with diode D3, inductor L1 and capacitors C3 and C4.
Get this Circuit
The idea for this circuit came when I was repairing my aunt’s emergency light. Bulb based emergency lighting has a low efficiency and ultrabright l.e.d.s provide greater efficiency and more illumination, with a much extended battery life. It was therefore decided to change from a 12V light bulb to a pack of l.e.d.s. To get constant light, a constant voltage technique was adopted, using the circuit in Fig.2. For more power saving, step-down switching is used in preference to step-up. This function is provided by IC1 in conjunction with diode D3, inductor L1 and capacitors C3 and C4.
Get this Circuit