In EE 230 (Electronics and Systems) Fall 2022, we had a small project over a couple of weeks to design a circuit that would change what LED was turned on based on what temperature a sensor was reading. The challenge was that the sensor needed to turn on lights at one temperature and turn it off again at another. The temperature sensor output had different voltage depending on the temperature that it was sensing. Fortunately, a year prior I had heard an upperclassmen mention a hysteresis circuit to implement just such a function. With a bit of research, I found a nice document describing the math and the circuit which my lab partner and I implemented. We started our implementation by doing the math described in the document for each of the LEDs for their on and off conditions. Then we simulated it on an simulator called Falstad to ensure our math was correct. Once everything was working properly, we made the circuit on a bread board and verified it worked as intended. We ended up struggling to get it to work on hardware initially and solved our problems by using a better op amp. This taught me the importance of knowing that Op-Amps do not function as perfectly as the ideal op-amp. I really enjoyed this project because I could use information I learned in Solar Car and it was really cool to see it functioning properly. I also implemented the circuit with a microcontroller as a joke because the project description never said we explicitly had to do it analogly and could not do it digitally, although the lab TAs shot down that plan.