|Created||September 04, 2012|
|Last modified||September 04, 2012|
|Tags||joule-thief timed-light timer|
A simple single coil Joule Thief with a timer function.
A single coil Joule Thief light with a built-in timer.
Pressing SW1 will start the timing cycle which is approximately 40 seconds x Cx (uF). D1 and C2 steal some of the output to improve efficiency and to act as a capacitance multiplier to keep Cx small. With the values shown the delay is 3.5 minutes.
Brightness can be further improved by substituting a BC337 and BC327 for the NPN and PNP transistors.
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