electronic lab report with multisim

ENEE 3517 – Spring 2017 , Lab 9 Handout, Dr. D. Charalampidis Page: 1/2 ENEE 3517 – Electro nics Lab 9 – Spring 2017 Precision Rectifiers The objective of this lab is to build precision rectifiers using an LM 741 operational amplifier. Notice that the feedback is negative in this case. In Lab: 1. Build the following circuit for R = 1k. Use a sinusoidal input of frequency 1kHz and magnitude 5V peak. Observe signals vA and vo at the oscilloscope. Try to get pictures of as accurate waveforms as possible. You may have to “zoom in ” the voltage signals , especially at the peaks and when they are close to 0 volts. You may do so by choosing a ppropriate voltage and time scales. LM 741 Diagram: Brief introduction to the operation of the above circuit : The voltage at the output of the operational amplifier, vA, is be equal to the difference between the input voltage and vo times the amplifier gain, A. In other words, it will be vA = A(vi - vo). If the diode is “ON ”, then vo = vA – 0.7V, and if it is “OFF ”, then vo = 0V, because there cannot be any current on R (the diode is “OFF ”, so there is no current coming from that branch, and there cannot be any current going into the operational amplifier ’s negative input) . ENEE 3517 – Spring 2017 , Lab 9 Handout, Dr. D. Charalampidis Page: 2/2 2. Build the following circuit for R = 1k. Again, use a sinusoidal input of frequency 1kHz and magnitude 5V peak. Observe s ignal vo at the oscilloscope. Observe signal vo at the oscilloscope. As in part 1, t ry to get pictures of as a ccurate waveforms as possible. Again, y ou may have to “zoom in ” the voltage signals by choosing a ppropriate voltage and time scales. For the report: 1. Simulate the circuits above. 2. Do the circuit analysis for both circuits and compare with the results in the lab. For the analysis, d o not assume that the gain of the operationa l amplifier is infinite, but a large number, A. In other words, you have to use that the output of the amp lifier is equal to A( V+ – V-), where V+ – V- are the voltages at the posit ive and negative input terminals , respectively , of the operation al amplifier. 3. As always, include all necessary parts for the report as state d in the syllabus.