potential difference. A difference in electrical pressure. A potential difference exists when one component, or point, has an excess of electrons (a negative charge) and another has a deficiency of electrons (a positive charge). Potential difference is measured in volts.
potential drop. A drop in voltage in an electrical circuit caused by current flowing through a resistance. The amount of potential drop, which is also called a voltage drop or an IR drop, is determined by both the current and the resistance.
potential energy. Energy possessed by an object because of its position, configuration, or the chemical arrangement of its constituents.
potentiometer (electrical measuring instrument). An electrical instrument that measures the voltage of a source without taking current from it. The unknown voltage is compared with an adjustable voltage that can be accurately measured. When no current flows between the two voltage sources, they are exactly the same.
potentiometer (variable resistor). A variable resistor with three terminals, or connections. One connection is made to each end of the resistance element, and a third connection is made to a wiper that can be moved over the resistance element. The position of the wiper determines the amount of resistance used in the circuit.

pot life (resin specification). The length of time a resin will remain workable after the catalyst has been added. If a catalyzed material is not used within its usable pot life, it must be discarded and a new batch mixed.
potted circuit. An electrical circuit in which all the components are protected by encapsulating them in an insulating potting compound.
potting compound. A liquid plastic resin poured over electrical components in a potted circuit. The potting compound cures into an insulating, rubber-like solid that protects the parts from moisture and physical damage.
pound. A commonly used measure of weight or mass in the English system. One pound is equal to approximately 0.454 kilogram.