Amperage - Unit designed to measure current flow. Current flow is the movement of electrons. Measured as amps (A). One amp is approximately 6.28 billion electrons flowing past a given point in 1 second.
Closed Circuit - A circuit that is closed means current is allowed to flow through the circuit to ground.
Common Ground - Any conductive material that is either directly or indirectly connected to the battery negative terminal.
Conductors - Material that easily allows current flow and offers low resistance. (Example: Metal, Copper, Water)
Insulators - Material that does not allow easy current flow and offers high resistance. (Example: Rubber.)
Ohm's Law - A calculation method used to determine amperage, voltage, or resistance in the circuit when at least two of the three are known. A more detailed explanation is available HERE
Open Circuit - A circuit is considered open if a complete electrical path to ground is not available so current can not flow.
Parallel Circuit - Allows multiple paths of electricity from power to ground. Each split is considered a seperate leg. Each leg of these circuits can be another parallel or series circuit.
Pulse Width Modulation - Computer controlled supply of power that comes in on/off pulses. Allows intermediate positions. On time is measured as duty cycle.
Resistance - Forces trying to stop the flow of electricity. Any resistance creates heat. Measured in units called Ohms.
Series Cirucit - Allows just one path for electricity to travel from power to ground through all loads.
Voltage - Force that develops between electrons and protons; electrical pressure and also known as electrial potential. It does not flow, it is only the pressure that forces electricity to move. Also known as EMF. Its measured in VOLTS (V).