I have shown below an opamp circuit.here G2 is ground taken from the common(black knob) of dual supply shown below.
Now i have two doubts.
- For the ground we used the "common" of dual supply. But why we don't use "GND"(the green knob on the dual supply)?. What is use of that green knob? Is "GND" with same potential of earth? Which is the real ground for dual supply?
- In the opamp circuit we connect the three grounds( ground of opamp circuit, ground of input voltage and reference for output)in the same line in bread board. Is that allowable?. Because the negative of input voltage (dc power supply) is just relative lower potential abot it's positive. And what happens when different voltages are connected to same point?.