Fairy Flashing LED Lights


Posted on Feb 6, 2014

This simple and cheap circuit is not just for Christmas! There are just two resistors, a small-signal transistor such as a BC547, one flashing` LED and a string of normal` LEDs. The flashing LED works as an oscillator and switches the transistor on and off; and the transistor switches all the other LEDs. An (unregulated) 12 V mains supply can be u


Fairy Flashing LED Lights
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sed for power. No current-limiting resistor is required in the LED chain, because the forward voltages of the LEDs in the chain add up to the supply voltage. If red LEDs are used, with a voltage drop of 1. 65 V, then 12 V will supply seven; alternatively, use six yellow (2. 1 V each) or five green (2. 7 V). You can of course always mix the colours. Alongside the NPN transistor add a PNP transistor with its emitter connected to +12 V, with another string of LEDs connected down to ground. The two strings will flash alternately. Be the first of your friends to get free diy electronics projects, circuits diagrams, hacks, mods, gadgets & gizmo automatically each time we publish. Your email address & privacy are safe with us !




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