Wednesday, September 24, 2014

BRIGHT FLASH FROM FLAT BATTERY 3v WHITE LED FLASHER

BRIGHT FLASH FROM FLAT BATTERY
This circuit can flash a white LED, on a provide from 2v to 6v and turn out a really bright flash. The circuit takes regarding 2mA and recent cells are often used. the 2 100u electros in parallel produce a much better flash when the availability is 6v.



3v WHITE LED FLASHER
This will flash a white LED, on 3v provide and turn out a really bright flash. The circuit produces a voltage on top of 5v if the LED isnt in circuit however the LED limits the voltage to its characteristic voltage of three.2v to 3.6v.   The circuit takes regarding 2mA an is really a voltage-doubler (voltage incrementer) arrangement.
Note the 10k charges the 100u. It doesnt illuminate the LED because the 100u is charging and also the voltage across its invariably less than 3v. When the 2 transistors conduct, the collector of the BC557 rises to rail voltage and pulls the 100u HIGH. The negative of the 100u effectively sits just under the positive rail and also the positive of the electro is regarding 2v on top of this. All the energy within the electro is pumped into the LED to supply a really bright flash. 


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