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# May 2019 StudentZone Quiz Solution

Question 1:

How do you measure and computed the slew rate in the unity-gain buffer configuration? Compare this with the value listed in the OP97 data sheet.

Slew rate is defined as the maximum rate of change (slope) of the output voltage that the op-amp can deliver (change of voltage per unit of time).

The easiest way to measure the slew rate using the unity-gain buffer is to apply a square wave at the input.

Considering the unity-gain buffer configuration described in the lab activity, apply at the input a square wave having the frequency = 500Hz, minV = 0.5V, maxV=4.5V. Plot the input and the output voltages, then zoom in on the rising edge of the signal.

We can notice that the output voltages (CB-H) reaches the maximum value slower than the input voltage.

By computing the slope of the output signal (V/µs) based on the plot example above we obtain the slew rate as follows:

Question 2:

Summing circuit: using superposition, derive the expected transfer characteristic for the circuit of - find the output voltage in terms of Vin0, Vin1, Vin2 and Vin3. Compare the predictions of the ideal relationship with your data.