In electronics, an inverter can be defined as a device for converting direct current (DC) power into alternating current (AC). An example of an inverter is the adapter used in cars for converting the low voltage cigarette lighter’s power (DC) into mains equivalent voltage (AC).This allows the use of many types of household electrical devices while on the road. In a laptop, an inverter is often used to light the computer's screen.A laptop inverter is a small circuit board, usually about the size of a pen. Internally, a laptop runs on a low voltage, with the exception of the screen, which uses a backlit liquid crystal display (LCD).Without the inverter and the bulb it powers, the screen would be too faint to see properly.n a laptop, an inverter is often used to light the computer's screen. A laptop inverter is a small circuit board, usually about the size of a pen.