Attached is a circuit diagram of a simple photometer. I've just forgotten what I've learnt on electronics... So I'm not quite sure what are the functions of the 2 operational amplifiers in the circuit.
TP1 (I think it's controlling the voltage..?) is adjusted by the user and the readout is TP2.
It would be glad if any of you can provide some help on this question. Thanks!
Opamp on the left is an comparator that it(ab)used to control the power true the led. The opamp on the right is a non inverting Amplifier that amplifies 11x
I suppose it should be an amplifier - but the drawing is wrong. The midpoint beween the resistive divider must be connected to the inv. input terminal.