In this video, I show the circuit for a simple sound-level indicator and demonstrates how it works. Circuit may be found at http://clydelettsome.com/blog/product/sound-level-indicator-schematics-and-parts-list/
Demonstration of a simple light sensitive switch made with an op-amp configured as a comparator. Obtain schematics for Free at http://clydelettsome.com/blog/product/light-sensitive-switch/
Demonstration of a simple calculator made of seven segment displays, seven segment drivers, AND, OR, NOT, and EXOR gates that add two numbers together.