AC Power Sources

AC Power Source FAQ

What is AC?

An alternating current (AC) is an electric current that periodically reverses polarity and continuously varies its magnitude over time. Businesses and residences use AC power because it is less costly and more efficient for generating and transmitting than direct current (DC) power. Transformers can step up the voltage of an AC line or step it down to reduce power losses during transmission.

AC power is the kind of electrical energy residential homes receive — consumers use AC power when they plug TVs, appliances, and other devices into the wall. AC power is then converted to DC power which nearly all electronic devices use.

What is an AC Power Source?

An AC power source supplies AC power to a load. The power input can be either AC or DC. You need AC power sources because power supplies from wall outlets do not meet the load’s specifications. For the load to function correctly, an AC power supply transforms and tunes AC power from the electrical source to the voltage, current, and frequency levels the device requires. This is achieved by stepping up or down the voltages, and then filtering the signal.

You can use an AC power source for testing purposes. An AC power source can simulate electrical grid interruptions, harmonics, surges, or other events that could cause a device under test (DUT) to fail.

What is the difference between a DC and AC power source?

AC power delivers electricity over distances and distributes it via electrical grid systems.

DC power provides a one-directional flow of electric charge, and while it is a more reliable form of electricity, it sacrifices distance. Most electronic devices use DC power because the voltage levels are so consistent — for example, devices that use batteries. Or, devices convert AC power to DC power using a rectifier. Power supplies often have built-in rectifiers and transformers to increase or decrease the voltage to the right level.