Definition of Terms Used

Alternating Current (AC)

The type of electrical power supplied by utilities or made when a generator is run. The unique characteristic of this form of electricity is that it reverses direction at regular intervals. For example, 120 Vac 60 Hz. power reverses flow 60 times a second, hence the rating 60 Hz. (cycles).


A measurement of the flow of electrical current. One amp is equal to the electric force of one volt acting across the resistance of one ohm.

Amp Hour

One amp of electrical current flowing for one hour. Expresses the relationship between current (amps) and time. (OHMS law I =V/R)


The rate of flow of electrical charge. The flow of amps is often expressed as current.

Direct Current (DC)

The type of electricity stored in batteries and generated by solar electric devices. Current flows in a single direction.


When used in reference to utility power, it refers to a system of electrical transmission and distribution lines.

Ground Fault Protection (GFP)

A circuit protection device that prevents the flow of electrical current to earth if a short circuit is present. Usually required in wet locations-e.g. for outdoor, kitchen and bathroom circuits.

Hertz (Hz.)

The frequency, or number of times per second, that the flow of AC electricity reverses itself. Also referred to as cycles (see alternating current).

High Battery Protection

A control circuit that disconnects charge current flowing to a battery when voltage reaches a dangerously high threshold. Prevents damage created by excess gassing (or boiling) of electrolyte.

Idle Current

The amount of electrical power required to keep an inverter ready to produce electricity on demand.

Kilowatt (kW)

One thousand watts of electricity. Ten 100-watt light bulbs use one Kilowatt of electrical power.

Kilowatt hour (kWh)

One kW of electrical power used for one hour. The most common measurement of electrical consumption, most grid connected electrical meters measure kWh for billing purposes.

Light Emitting Diode (LED)

A device used to display various status functions.


Any device that consumes electricity in order to operate. Appliances, tools, and lights are examples of electrical loads.

Low Battery Protection

A control circuit that stops the flow of electricity from batteries to loads when battery voltage drops to dangerously low levels.

Modified Sine Wave

An AC wave form (generated by many inverters) that is a pulse width modified square wave. It consists of a number of very small on/off steps rather than a fully smooth wave.

National Electric Code

A consistent set of electrical wiring and installation standards used in the United States.

Off Grid

An electrical system that is not connected to a utility distribution grid.


A device that displays the wave form created by an electrical generating device such as a generator, inverter, or utility.

Overload/Over-current Protection

A control circuit designed to protect an inverter or similar device from loads exceeding its output capacity. (A fuse, for example, is an over-current protection device.) All Trace inverters have internal circuitry to protect themselves from overload/over-current conditions.

Sine Wave

The output wave form of an electric generator or utility. A smooth wave going above and below zero is created. This wave form is also produced by sine wave inverters such as the Trace SW and CO-Sine series.

Surge Capacity

The amount of current an inverter can deliver for short periods of time. Most electric motors draw up to three times their rated current when starting. An inverter will “surge” to meet these motor-starting requirements. Most Trace inverters have surge capacities at least three times their continuous ratings.


A unit of measure of the pressure in an electrical circuit. Volts are a measure of electric potential. Voltage is often explained using a liquid analogy-comparing water pressure to voltage: a high pressure hose would be considered high voltage, while a slow-moving stream could be compared to low voltage.

Watt Hour (Wh)

Electrical power measured in terms of time. One watt hour of electricity is equal to one watt of power being consumed for one hour. (A one-watt light operated for one hour would consume one watt hour of electricity.)