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Transistor and inductor based 1W emergency light. Answered

I made this 1w emergency light circuit for the maximum output (consuming less power to deliver maximum brightnes) from the LED. But during its functioning, i found that the led glows with same brightness as it was without the circuit ( directly connecting it with battery). Please, suggest some alternatives or amendments to be made.
I have uploaded an image of my circuit.

Tags:light

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Jack A Lopez

4 years ago

This is just a guess, but I am thinking this circuit might require V1, the battery voltage, to be significantly less than the forward voltage drop across the LED. Call that voltage VLED. In other words, the circuit wants: V1 < VLED

The typical forward drop across a white (or blue) LED, is around 3 to 4 volts, depending on the LED. Guess VLED= 3.5 volts. So for this circuit, as shown, the battery voltage V1 and VLED are roughly equal, and that might be the problem.

Some things to try to satisfy this inequality condition, V1 < VLED, include:

Replacing the battery with one with a much lower voltage, like a single AA battery, so that: V1 = 1.5 V < 3.5 V = VLED

Replacing the white LED with two white LEDs in series, so that:

V1 = 3.5 V < 7.0 V = 2*VLED

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mpilchfamily

4 years ago

Assuming the LEd's specs are similar to this one.

http://www.adafruit.com/products/518?gclid=CjwKEAj...

Connecting it directly to the battery without anything else it will draw close to it's maximum current and give you maximum brightness. No need for additional driver circuitry. Nothing more you can do to make it brighter.