I used 100 ohms accross the photo darlington and the voltage obtained from it is 360mv i need 3volts to give input to AD630 for lockin amplifier application.
inorder to increase the voltage shall i use INA 121P of 10 gain? or 100 gain or 1000gain .
What is the pull up resistor and voltage coming back down the line from the lock in amplifier? To get the maximum voltage change from the photo darlington, earth the emitter and connect the collector to a +Vcc via a high value resistor.
Frank
If you get 360mV across your 100 ohms, then the current through it is .36/100 = 3.6 mA. If this current flows through a 10 K resistor then the voltage drop across it will about 4.8V. As I said earth the emitter and return the collector to the +5V rail via a 10K and take the output from the collector.
Frank