Li Battery Voltage Boosting Circuit for 4 LEDs

Image 1: Basic circuit using a 5.1 KΩ Base resisitor

The basic circuit used the standard best loops ration 8 by 20 loops on the toroid and was powered by a Li 18650 battery starting at ~ 4.2V.

Image 2: Rebuilt circuit using a 5.1 KΩ Base resisitor

The rebuilt circuit used the same 8 by 20 turns on the toroid but instead of using a Li battery starting at ~ 4.2V it was using a DC power supply of about 3.76V.

Image 3: Rebuilt circuit using a 10 KΩ Base resisitor

The peak voltage when using a 10 KΩ resistor was observed to be anything from 16.6 to 17.2 Volts.

The rebuilt circuit, using either resistor, shows a slightly longer off time to the on time. The original "basic" circuit showed an on/off time ratio of 1 to 2, the rebuilt circuit shows the ratio as 1 to 2.5 so approximately 25% more off time. I think this is beacuse for the "basic" version I used a pre-wound toroid I had in the drawer so I don't know the loop ratio for that version but for the "rebuilt" version I know I used the best ratio of 8 to 20 loops.

On the other hand, the difference may simply be that I tested the "basic" version using 4.2V and the "rebuilt" version using ~3.75V since the power supply to be used for this circuit was known to be running at 3.76V.

Image 4: Circuit board Above View

Image 4: Circuit board Below View

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