Proper way to disable Newwish APC

[LarryQ]

In those Newwish (dx) lasers that make use of a photodiode APC.

Does simply cutting one of the wires work to disable it?

OR should a static value resistor or a simple wire jumper be placed across the APC wiring pads after cutting the wires?

Larry

 

[laserrod]

My 30mW has a extermnal PD wired backwards. It is two wire that go to the brase optics tube. The battery current should MAX about 230mA.

Ans.:  cutting a wire to PD will disable it if it's correctly wired.

The circuit is 2 parts: a fixed current limiter with priority and a PD half that is adj...

The circuit needs  3v Min. and won't get it from 2 batts. as designed.
If I put 4.3v on my driver the batt. current is @400mA.

The circuit is designed for 5v I think.  That could blow the LASER diode!

If you remove the 3.9k Res. connected the 15k, the current should go up....

The circuit is a crap-shoot. The current path has more voltage drops and that adds up to more than the source voltage. Go figure that!!

Cheers [smiley=beer.gif].