Ashok constant voltage transformer (CVT) work on the phenomenon of Ferro-resonance, i.e., on the principle of magnetic core saturatio. Ferro-resonance occurs when non-liner (saturated) magnetic reactance is connected is series with linear capacitance and resistance. Stab-Pro CTV is the idlest unit for applications with computer, photocopiers word processors, printers, etc. The output is corrected in 25 to 30 milliseconds. it provides clear voltage free of spikes. The accuracy in output voltage regulation is a major advantage of this CVT. it normally gives 3% regulation.