LM317T Voltage Regulator with Pass Transistor

A 7805 voltage regulator burning because I accidentaly switch the voltage polarity



http://www.youtube.com/watch?v=cFwMGPuk9gg&hl=en

This is a 1.1w 445nm(Blue) burning laser. it is housed in an altoids box and thermal paste connects the diode to the box for cooling. the circuit is a lm317t and a 1-Ohm resistor along with a 47uF 35V capacitor. a 9v battery was used, even though the rating for a typical 9v is around 0.55Ah ( which means it wont power it for more than 28 minutes) and the lithium version can power it for at most 58 minutes with a rating of 1.2Ah



http://www.youtube.com/watch?v=W-YidkTB37c&hl=en

LD1236VL (Sony) High Power AlGalnP Laser Diode Fixed and improved: * Faster burn time, only 1 sec. (with correct focal point) * Added a voltage regulator so that the voltage will be constant even after a 100 burns. * Reduced weight by using 9V battery instead of 4x AAA battery. ( well, the main reason for using a 9V battery is that 4xAAA only gives 5.7V max and if I wanna regulate 5.7V constantly is impossible. The regulator can only provide output voltage not larger then the input voltage. a 9V battery tipically drop from 9.xV (brand new) to 8.xV ( almost exhausted) 2.5V, 250mA, approx 150mW optical output power. Using LM37 voltage and current regulator for input stability. ** when added LD, the V-LD should be about 2.5V! not 5.7 or 5.23! ** the 5.7V is only the circuit output rating, no load ( R-LD ).



http://www.youtube.com/watch?v=tSi69jQpl7E&hl=en

electromunk.com Made this laser out of stuff I had laying around. Driver based around the LM317 voltage regulator(set at 420mAh).



http://www.youtube.com/watch?v=mLHlvgvxXo0&hl=en