Electrical Basics

(adapted from Tom Igoe's book on physical computing)

• Electricity always follows the path of least resistance to ground.
• A circuit is a closed loop containing a source of electrical energy and a load. The load transduces electrical energy into light, heat, ...
• Water analogy: The flow of electricity through a circuit is like water flowing through a pipe. Electrical current is like the amount of water flowing through the pipe. Voltage is analogous to the pressure or speed with which the water flows.
• A switch breaks a circuit and prevents electricity from flowing.

Ohm's Law

Voltage = Current*Resistance

V=IR

Circuit Schematics

Comprehensive list of frequently used symbols

Voltage Divider

http://ccrma.stanford.edu/courses/250a/lectures/electronics/