Day 11

Today we went over inverting, non-inverting, summing, and difference amplifiers. Also, we did labs on summing and difference amplifiers.

Here we took a look at the effect of waves when saturation in the amplifiers occurs. We found a saturation voltage output of around 4.2V and -3.5V with the op amps used in class.

Above is an example problem of an inverting amplifier where we used nodal analysis to find Vo.

Above is a derivation to find Vo on a non-inverting amplifier in terms of Vi, Rf and Ri.

Summing Amplifier Lab:

The purpose of this was to compare measured output voltages with theoretical output voltages.

For our pre-lab, we were to find a ratio of resistance values Rf/Ri such that we wont reach saturation voltages. We picked 6.8kOhms for Ri and 3.9kOhms for Rf (Ri=R1=R2 and Rf=R3). The equation left of our table is the equation that was derived for Vo.

Above is our circuit set up. Unfortunately we did not take a picture with the waveform generators wires hooked up.

Based on our results, we can say that our derivation to determine the output voltage is goo since most of the voltages were at a small percent error. We believe any error in are measurements is due to treating the op amp as ideal and resistors to have exact resistances throughout the experiment.

The purpose of the Difference Op Amp Lab is to compare theoretical output voltages with measured values.

 
Is the result of the derivation for output voltage on a difference amplifier in terms of input voltages and the four resistors. But when all resistors are equal to each other, the the output voltage is just Vo=V2-V1. We will be testing this case in our lab. 

Above is a picture of our circuit and measurements made for the lab.