Signal Generators - Circuits This page relates to Signal Generators circuits, schematics or diagrams. Discovercircuits is your portal to free electronic circuits links. Copying content to your website is strictly prohibited!!! How to Build a Simple Function Generator Circuit with an A function generator is a electronic device that can produce a variety of different waveforms. The one we will build can output square, triangle, or sine waveforms. Through these 2 pins, we establish the positive and negative DC rails from the AC signal can swing. The LM324 can take in a maximum of up to 30V to pin 4, VCC.