Constant voltage transformer, Constant Voltage transformer – CVT use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output with a varying input. The ferroresonant approach is attractive due to its lack of active components, relying on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage. All problems related to variation fluctuation in Voltages are effectively handled because of this principle and a constant voltage output of ± 1% is given.
Features for CVT :
No Semiconductor or moving part used, hence very high reliability.
No feed back control used.
Intrinsic current limiting and short circuit protection.
Energy storage for line loss up to main 3ms at typical load.
Short term over load capacity.
Higher input voltage control range for load less than rated low.

Constant voltage transformer, Constant Voltage transformer – CVT use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output with a varying input. The ferroresonant approach is attractive due to its lack of active components, relying on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage. All problems related to variation fluctuation in Voltages are effectively handled because of this principle and a constant voltage output of ± 1% is given.
Features for CVT :
No Semiconductor or moving part used, hence very high reliability.
No feed back control used.
Intrinsic current limiting and short circuit protection.
Energy storage for line loss up to main 3ms at typical load.
Short term over load capacity.
Higher input voltage control range for load less than rated low.