deep red design

I want to build my own astronomy flashlight. There are some great designs out there but I want to be able to choose the LEDs and the colour.

I found a good circuit design at the Renewable Energy UK website. It features pulse width modulation (PWM) based on a IC 555 timer.



The notes are quite good. For example, they suggested using germanium diodes in place of signal diodes so that the dimming range can be extended to go from 1% to 99%.

I tried the circuit on the electronic kit at 9 volts with water clear red LEDs and it worked good!

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Bought most of the bits at Sayal: 555 timer, 1k resistor, etched board, NPN transistor, diodes, electrolytic capacitor, regular caps, and project box. All for around $20. Couldn't find really small potentiometers...