Hi,
for my dummy load project I wired up a non inverting summing amplifier on my breadboard according to this circuit diagram (my own).
I wired it up slighly different, but quite similar:
- Only 1 pot for adjusting the gain (RV5)
- Only two 10K summing resistors (R4, R5) on the input pin 3
When I short the input pins 2 and 3 together I get around +11mV offset on the output pin 6. The OP I am using is a TS271 from ST (TLC271 equivalent).
When I turn the potentiometer RV4, nothing happens. I am not sure why.
I also tried a smaller single turn 5K pot, but no success.
Shouldn't I be able to adjust to wind this voltage down to zero volts this way?
Is it possible that I either need a negative voltage supply or a rail-2-rail OP to go down to zero volts?
Any help is appreciated.
Cheers,
Florian