I have been tasked with creating a logic probe that reads High/Low/High Impedance, but what works in simulations, isn't working in practice.
This was my idea:
I made a symmetrical power source using two resistors and a virtual ground, and fed the 741 OP AMP using these +VCC/2 and -VCC/2. The idea was for the probe voltage to be compared to half VCC, that way we'd get a -VCC/2 to +VCC/2 voltage output, and if there was high impedance, both LEDs would be off.
What ends up happening however, is no voltage output. I think the problem is in the symmetrical power source, because whenever the OP AMP is connected to the circuit, the perfect VCC/2 equilibrium between the two resistors is gone, and it goes to like 4v or whatever when feeding it with 5v.
Any ideas on why this circuit doesn't work? I have tried searching for ways to create a symmetrical power source, but all of them give me the same simulation results, so i figured it wouldn't change on practice.