operational-amplifierorcadoscilloscopepspice
I created the circuit for a project of mine on Orcad Capture (Pspice). I ran a DC sweep on it and got the desired output. Now I have built the identical circuit on a breadboard but I am not getting the same output on the oscilloscope that I am on the DC sweep graph on my simulation. Is there a certain way to do a DC sweep on an oscilloscope?
Here is my circuit:
Here is my DC sweep graphical output:
Here's the pin-out of a 741: -
Please note the following: -
Create a current source whose AC magnitude is 1A. Connect one terminal to GND, and connect the other terminal to the appropriate pin of the device under test. Do an AC simulation, and plot the voltage on that pin. Remembering that \$Z(j\omega)=V(j\omega)/I(j\omega)\$, and since \$I(j\omega)=1\$ (because you've set it to 1), then the impedance is simply equal to the voltage: \$Z(j\omega)=V(j\omega)\$.
You might be concerned that 1A is a lot of current for your circuit to handle. But it doesn't matter: AC simulations are, by nature, small-signal analyses. Namely, when doing an AC simulation, the DC operating point is computed first and the AC relationships are found without consideration to AC amplitudes -- i.e., assuming small-signal conditions. So even with a 1A AC current source, the AC analysis is still a small-signal analysis, even if your circuit couldn't handle that level of current in real life (or even in a transient simulation).
Best Answer
Not without other equipment - modern scopes generally do not have an X output.
You will need a function generator that can output a triangle or sawtooth waveform. Feed the sawtooth signal into the circuit under test and the output into the Y input scope.
If the scope can do an X-Y display then feed the signal from the function generator into the X input. The scope will then display the DC sweep of the circuit.
If the scope does not support X-Y display you can simulate it by triggering the timebase with the start of the sawtooth from the the function generator and adjust the timebase to display a single cycle.
The frequency of the function generator may require some experiment - from many seconds to tens of cycles per second. A lot may depend upon the value of any decoupling present in the circuit.