   Many times we want a simple power supply to operate our low power electronics or electronic circuits. Most of the power supplies use transformers but there is also some tricks to get voltage of your needs from transformerless power supplies. Transformerless power supplies are very

important and works well on the places where you have short place and low mA requirements. The circuit mentioned here is a simple and verastile power supply circuit which is capable of delivering any voltage from 3 to 12 volts by selecting suitable parts values you can obtain voltage of your needs.
Here are some details of part values you can change to get the required voltages.
For  3V Use  R2 = 15K, D2 = 3V & C1 = 220µF
For  6V Use  R2 = 12K, D2 = 6.2V & C1 = 220µF
For  9V Use  R2 = 10K, D2 = 9V & C1 =  220µF
For 12V Use R2 =  10K, D2 = 12V & C1 =  470µF

Note: Many of its points are at AC mains voltage. It could give you lethal shock if you are not careful. If you don't know much about working with AC line voltages do not attempt to construct this circuit.

Transformerless Power Supply  