Feb 08 2011

PWM Fan controllers using the 555 timer IC

Here I made 3 slightly different PWM fan controllers based on the 555 timer for controlling a large server fan – Delta FFB1212EHE, 3A peak, 2A normal load, other features of these controllers are to boost the fan on to 100% for the first few seconds of receiving power and a ‘turbo’ button to set …

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Jan 20 2011

Joule thief

In case you’ve not heard of a joule thief before, they’re simple voltage boost circuits, usually used to drive light loads like LEDs with a single battery cell, even batteries that other electronic devices consider ‘dead’ can be used, [Wikipedia article]. I made 2 versions of the joule thief, the common one with a single …

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Jul 25 2010

FM Radio Transmitter

Here’s a nice little FM radio transmitter, it has a range of about 100m – 200m with a 12V supply, decent audio quality and the microphone is very sensitive, with a 5pF – 30pF variable capacitor the transmitter can tuned between 87.5MHz – ~98MHz, however at the higher frequencies it’s much less stable and more …

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