KEYCHAIN LASER DRIVER CIRCUIT
This is a simple description (some kind of engineering reversing :-)) of cheap KeyChain Lasers that are sold for 5 bucks or so.The laser diode head has three pins labeled: LDC (Laser Diode Cathode), PDA (Photo Diode Anode) and COM+ (common Positive Terminal).Inside the laser diode head we find the laser diode itself and a photodiode, used to regulate the laser diode current with an external feedback loop.
   KEYCHAIN LASER DRIVER CIRCUIT
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