What are Voltage Stabilizers

As the name suggests, a voltage stabilizer stabilizes or regulates the voltage if the supply voltage varies or fluctuates over a given range.

It is an electrical appliance that feeds constant voltage to a load during over and under voltage conditions. This device detects these voltage conditions and correspondingly brings the voltage to desired range.
Voltage stabilizers provide a means to regulate the supply voltage to the load. These are not meant to provide a constant voltage output; instead it operates the load or system in an acceptable range of voltage.

The internal circuit of a stabilizer. It consists of auto transformer/ transformer, rectifier unit, comparators, switching circuit and relays.


In case of modern digital type stabilizers, a microcontroller or microprocessor is used as central control unit.
There are different types of voltage stabilizers available in today’s market from various manufacturers. Stabilizers come with a different KVA rating for normal range (to produce 200-240V output with 20-35V boost-buck for input range of 180-270V) as well as a wide range (to produce 190-240V output with 50-55V boost-buck for input range of 140-300V) applications.

These are available as dedicated stabilizers for various homes as well as industrial appliances such as air conditioners, LCD/LED TV, refrigerators, music systems, washing machines and also available as a single large unit for all appliances.

Stabilizers consume very less power, typically about 2 to 5% of maximum load (i.e., rating of stabilizer). These are high efficiency devices, typically 95 to 98%.
These can be single phase or three-phase voltage stabilizers. Both non digital and digital automatic voltage stabilizers are available from well recognized manufacturers.

Some additional features are available in modern stabilizers that include high voltage protection, overload protection, zero voltage switching, frequency variation protection, voltage cut off display, etc.