Question by Anirvan Kule: Why do the step-down transformers available in the local market has a very high output voltage (AC) than their rated voltage? Suppose a 0-12 V, 3 Ampere transformer gives up to 16 or 17 volt AC on secondary side which peaks to around 23 Volt after filtration at no load while it should be maximum 17 Volt dc peak if it was 12 V AC?
Comment by Akshay EFU: Because non-switching transformers work by induction, the open load voltage will always be higher than the target voltage. Connecting a load creates a voltage drop which will be equal to the rated output voltage. Try switching to a switched mode power supply for a regulated voltage.