We will only deal with electrical circuits with direct currents, and not alternating current. Negatively charged electrons, which have a very small charge but can have appreciable potential energy, will flow from the negative terminal of an electrical circuit to the positive (Ben Franklin assumed that current flowed in the opposite direction). Resistance is expressed in units of ohms (Greek capital omega Ω) and is the ratio of volts/current. Electrical circuits may be broken into series and into parallel. We also use a “Power Law” to describe the electrical power dissipated in a circuit. Current flow obeys Ohm's Law and Kirchoff's Voltage and Current Laws. The “efficiency” of an electrical circuit means having good conductors in the leads compared to the main device in the circuit – a fact exploited by Edison making possible his electric lightbulb. The simple electric switch turns out to be the core technology in modern electronic computers. Key Words: electrical circuit, direct current, alternating current, electrons, Ben Franklin, resistance, ohms (Greek capital omega Ω), series circuit, parallel circuit, Ohm's Law, Kirchoff's Laws, current divider, voltage divider.