Answer :
An auto-transformer is used in stepped voltage stabilizers, as it is capable of adjusting its output to compensate for input voltage fluctuations, ensuring stable voltage delivery. So the correct option is 3. Auto-transformer.
The type of transformer used in a stepped voltage stabilizer is an auto-transformer. Voltage stabilizers are designed to maintain a constant voltage level for electrical devices, ensuring their safe operation. The auto-transformer adjusts its output by selecting different taps on the winding, providing a variable voltage output to compensate for fluctuations in input voltage. It serves the double function of transforming the voltage up or down while stabilizing it. Unlike traditional transformers, the primary and secondary windings are connected in an auto-transformer, and it has a single winding that acts as both the primary and secondary winding.
This concept differs from small transformers, which typically refer to transformers with low power ratings. Current transformers are intended specifically for measuring and monitoring current, not for voltage stabilization. Boost transformers, on the other hand, are designed to increase the voltage level, but not adjust it based on input variation like an auto-transformer does in voltage stabilizers. So the correct option is 3. Auto-transformer.
