Appendix C: Glossary and Abbreviations

Current (i)

The flow of electical energy, measured in amperes (A) or amps for short. By convention, current flows from the positive side of a circuit to the negative side. [Note that the actual charge carriers, electrons, flow from the negative side the positive side!]

Electricity

A form of energy resulting from the accumulation or movement of charged particles, typically electrons. Practically speaking, electricity is a form of energy that we use to generate heat, light, and movement.

LED

Light emitting diode; a semi-conductor designed to emit light when a current is applied.

Power (P)

The rate of work, measured in Watts (W). Practically speaking, power is the rate at which a circuit converts electrical energy to another form of energy (such as light).

\[ P = V i \]

Resistance (R)

The resistance to current flow, measured in ohms (\(\Omega\)).

\[ R = \frac{V}{i} \]

Voltage (V)

The potential energy difference between two points in a circuit measured in volts (V). A larger voltage indicates a stronger “push” to drive electric current.