Custom SCR Dimmer (ECE304 Final Project @uwmadison)

An SCR Dimmer modifies the firing angle of a silicon controlled rectifier in order to control the amount of time that current is allowed to flow. This in turn limits the amount of power that is allowed to pass through the dimmer to the load. SCR dimmers are a useful way to control AC power and can be used in a wide variety of applications from dimming AC powered lighting to AC motor speed control. In this video I explain the basic operating principles of an SCR dimmer and describe a simple test setup to confirm functionality. I designed and built this SCR Dimmer myself in the Spring Semester of 2025. Note that in the video, only the negative half cycle of the waveform is dimmed as I burnt out one of the SCRs by accidentally short-circuiting the device during the early testing phases. I did not have another one handy at the time of filming, but I have since replaced it and confirmed that operation works significantly better. The basic principle is the exact same with both half cycles functional as it is with only one. Group members: Zerind Spore, Chase Wilber Professor: Giri Venkataramanan