Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2495336.

I created this transistor prop to help explain how a Bipolar Transistor works. The design has two main parts: the base and the lever arm. The lever arm represents the amplification of the transistor using water flow as current. A little water flow at the base flap lifts the emitter-collector flap much higher allowing more water (current) to flow.

Full explanation is in my Video: https://youtu.be/RI-7TyVWB3s

The waveform stl file has DC and AC representations as seen in the video.