Playing with white LEDs

White LEDs are available. It is fun to build simple light sources for different applications.

Here are some which I have built.

This circuit is ultra simple. It squeezes the last drop of energy from your battery too.

Permeability of the Amidon 77 ferrite material is high, u= 2000.

This is an oscillator which runs on about 25 kHz. When the transistor turns off, high voltage (>3V) is generated.

The same oscillator as above is here but in addition it is also oscillating on 1Hz giving short light pulses. I have many such

beacons in my garden…, like Christmas lights. Batteries last months, up to half year.

If you need some light in your house at night time, this generates just enough. And it can be on all the time.

To make it safe, good materials have to be used. Isolate from mains voltage, no compromises.

All fits into a large mains plug, which gives good isolation as well.

These are 1-2hours projects. Easy enough for beginners too. No printed circuits needed. Ugly construction is not too ugly.

Pekka OH1TV

15.3.2009