Day 12 (Day14 on notes)

Today we looked a little further into cascaded op amps and did a lab where we design a temperature measurements system.

Here we took a look at a comparison of an op amp and a darlington transistor and looked at the over all gain that can be found as a product of individual gains.

Above we did an example for cascaded op amps where we needed to find the current i_0 as a function of v_0.

Temperature Measurement System Design Lab:
The objective of this lab is to design a temperature management system using a thermistor, a Wheatstone bridge, and an op amp. With these three components we will be able to make a system that can detect a voltage change.

Above we built a Wheatstone bridge circuit and used a potentiometer to balance the voltage change of the thermistor to be zero at room temperature. So if the thermistor heats up and decreases in resistance, we will be able to measure that voltage change.

Once the Wheatstone bridge was balanced, we added an op amp to the Wheatstone bridge to amplify the voltage change. Above we can see how the voltage change was amplified as we heated the thermistor to body temperature.