I am trying to breadboard a DC circuit schematic (a sawtooth voltage controlled oscillator, to be precise). In the schematic there is a positive supply, a negative supply and ground (+4.5V, -4.5V and a ground, respectively).
I understand some things about the potential difference and the reference voltage. I tried to connect every pin which in the schematic is connected to the ground, with the negative supply. But I am sure that is not correct. I did a bit of research and now I know that the potential voltage difference between the positive and negative supply must be 9V and the ground is in the middle of this difference.
The problem is, I have a power supply device that has only Positive and Negative supply. So, what do you propose I do? I do not feel that it is correct to connect to the ground, every pin connected in the negative supply in the schematic. I am sorry if this exact question is asked again, but I am searching everywhere, even in stack exchange for over an hour now. Thank you in advance.
Best Answer
You need to provide both plus and minus 5 volts (not 4.5) for the schematic you provided.
Bipolar power supplies can be expensive, but you can fake one using two 5V "wal-warts" connected in series:
Then just connect the +5V, -5V and ground nodes in the schematic to the respective outputs shown above. As you can see now, -5V and ground are not the same.
Note: you can also do the same thing with two sets of batteries connected in series; the circuit may work okay with 4.5V, in which case you could use three AA or AAA cells in series for the top compound battery, and another three cells for the bottom one.