Project Description: This individual project was the final assignment for the Linear Circuit Analysis lab I took in Spring 2021. The task was to design and construct a basic audio equalizer circuit that could split a signal into treble, mid, and bass components via frequency-based filters, and then use potentiometers to control the amplitudes of each frequency region.
Big Wins: I was able to construct a functional circuit, and then use an oscilloscope to validate hand-calculated values of components that achieved desired cutoff frequencies.
Challenges: Upon first assembly of my circuit, I attempted to debug and couldn’t find a clear error causing the circuit to not function. I ended up stripping the breadboard and reconnecting components based on the same diagram and the circuit began working.
Key Takeaways: Wire management and pre-planning a rough layout of circuit components go a long way to make assembling and debugging circuits much easier.
Here is my final constructed equalizer circuit. The purple sticky note was to keep track of which potentiometer controlled which frequency band, and which direction was to increase volume.
This is the circuit I designed and implemented, drawn up in LTSpice, with sub-sections outlined by their function.
Here are three frequency response plots showing that the low pass, band pass, and high pass filters for bass, mid, and treble regions worked as intended
This plot shows four stages of amplitude for the summed volume of the system, from full volume to fully muted. The signal here was a signal consisting of a 1V DC offset, a 1V 1KHz sine wave, and a 0.2V 6KHz triangle wave which was used to independently verify the filters working