8. Change the frequency out of the function generator to 100 KHz and note the ef

Question

8. Change the frequency out of the function generator to 100 KHz and note the effects on th output of the circuit. This is an obvious disadvantage of the low-cost op amp used in experiment. Increasing the frequency of the input to 100kHz wher this will create an output waveform re the output's edges are no longer vertical. Use the Horizontal adjustment knob and the left/right adjustment knob to "zoom" in on a rising edge and get a measurement of V and . Convert or keep the measurement in s for the slew rate calculation. Compare your results to the expected 0.5V /us. Record the measured slew rate and the frequency of the input where your measurement takes place. WRITE-UP GUIDE Neatly sketch all input and output signals as required in the handout Analysis The following topics should be addressed in this section of the report 1. What is the difference between an inverting comparator and a non-inverting comparator 2. Briefly explain how slew rate of 0.5Vlus affected the output in step 8. 3. How close did the output voltages come to the power supply voltages? Compare this to the instructor's expected values of + 14V OFFSET 1 IN1 () 2 IN1 ( 3 VEE 4 8 NC NULL 6 OUTPUT 5 OFFSET NULL Figure 1: 741 Op-Amp Pinout Figure 2: Non-inverting Zero-Crossing Detector

Explanation / Answer

1). Non-Inverting Comparator: - Inverting input is held at refernce voltage , and the input voltage is applied at the noninverting terminal, and when noninverting terminal voltage is greater than reference then it comparator output is positive.
Inverting Comparator: - noninverting input is held at refernce voltage , and the input voltage is applied at the inverting terminal, and when inverting terminal voltage is greater than reference then it comparator output is negative.

2). If slew rate is 0.5V/us that means change is output voltage is 0.5V in 1us. When input signal is too fast(or frequency is large) then because of slew rate the non-inverting zero crossing detector will not recognize the input.

3).The output of opamp depends on the loading. So output will always be less than the supply voltage because it is using the BJT.

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