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Topic: simple circuit reverse engineering (Read 576 times) previous topic - next topic

ted

#30
May 20, 2018, 12:00 am Last Edit: May 20, 2018, 12:08 am by ted
For double op amp is almost standard - pin #4 is ground or minus and #8 is +, the easiest way to find out  where you connect the battery

ted


ted

Double check your drawing - op amp is in strange configuration
I did not notice that the op amp is upside down.

Correction
IN - to control laser beam
IN - photodiode modulation signal
Signal Out - from photodiode
Red + voltage supply
Black - voltage supply

TomGeorge

The reason I need to use that particular sensor is that I have 5 of them available, taken from old welding machines and doing that exact job of sensing the welding temperature.
How were they integrated into the old welding machines?
Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

cloxart

@Ted: you say black = -V, but black is going into OUT1??

@ TomGeorge: I have no way to check, they were originally mounted on some induction welding machines (CEIA LOGE 23) but the machines has gone and the manufacturer that I contacted said they do not have any documentations as it is a very old model.

ted

correction of correction


ted


cloxart

thanks Ted,
I guess I should start testing it... do you think I am correct in assuming that on the laser beam wire I must connect a current limited supply?

ted

All LEDs required current limit, the simplest is a resistor - 200 -300 ohm .
That is 3V laser diode.

LED wire (brown ) - required modulation signal,

google - chopper amplifier

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