User manual

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Expected results: Channel 1 of your MSO should display the 10 Hz sine wave being fed to the V_in pin of the op-amp,
while channel 2 should display a square wave resulting from the voltage level detector circuit (V_out).
Whenever the sine wave, observed on channel 1 of the MSO, is below 2 V, then you should expect the signal observed
on channel 2 of the MSO to be at 0 V. Alternatively, whenever the sine wave is above 2 V, then you should expect the
signal observed on channel 2 of the MSO to be at 5 V. Ideally, the high values are exactly 5 V, the low values are exactly
0 V, and the rise/fall times of the stimulus signal are minimal.
Observed results: The op-amp used is not capable of pulling the output to the exact values supplied to the V_supply ±
inputs. Therefore, in the output waveform (V_OUT), you may observe a high value of approximately 4.5 V and a low
value of approximately 1.5 V, as shown in Figure 4.13. For most digital input devices, logic low levels tend to be 0 V to
0.8 V, which would cause your signal to be incorrectly interpreted.
Therefore, to create an output signal that abides by typical logic level definitions, you should set the negative V_supply
input to something lower than 0 V, for example -1.25 V. This causes the voltage level detector to pull the output closer
to 0 V when the stimulus signal is lower than the 2 V reference voltage, as shown in Figure 4.14.
Figure 4.13. Raw Physical Circuit Test Results