Differential Amplifier Schematic
Dual polarity op amp circuit not working?
Can you tell me if this circuit will work for a dual polarity differential amplifier (instrumentation amp ina118)? It’s not working for me. What’s wrong with it?
http://img716.imageshack.us/img716/8839/42791210.png
Your have power supply design error. It requires dual power source with common GROUND. You do not need the 7805. Spite the 12 volts battery power source into half, bring one wire from the center (at the 6 volts point). It is the common Ground. Now connect +12V to pin 7, ZERO volt to pin 4. Power GROUND TO CIRCUIT GROUND. Re-do your circuit according to the DATA sheet.
Or connect the Zero volt (battery) directly to pin 4. Use the dual 7805 setup Ground to 1NA118 circuit Ground.
Op Amp Design Basics – Difference Amplifier -Subtractor – Part 5