A voltage stabilizer is connected to a power source that charges internal capacitors and batteries, which then supply power to connected devices rather than directly from the power source. The unit is able to maintain a fixed current even when there are power surges or drops.

A conventional voltage stabilizer normally has two circuits made from high resistant components. The input circuit is connected to the power input and is responsible for charging the capacitors. Digital gadgets draw their power from the output circuit charged by the capacitors. Both circuits have to work simultaneously to recharge the power consumed.

Due to the high resistance nature of voltage stabilizer circuits, the output power is often less than the input power. In such a case, the user may notice that equipment functions slower than it normally does. To overcome this issue, some stabilizers are fitted with power amplifiers. The amplifiers work by enhancing the rate at which batteries and capacitors are charging to ensure not too much power drain occurs when main power starts to fluctuate.

Most amplifiers automatically shut themselves off when input power is stable and start when power is fluctuating. This helps maintain a stable power output and greater performance of the voltage stabilizer and digital gadgets.