Help me build this Power Supply

Design the power supply that will provide a regulated 9V DC voltage from 220V,50Hz AC power supply.
Use a fullwave bridge rectifier(i.e 1N4739A,1W Diode)a 9V Zener diode and a 20:1 step down transformer.
You must include an LED to indicate when the power supply is ON.
Sketch the wave form at the output of each stage of the power supply and determine the value of F(output) and PIV,V(average),I(average)

Posted by Sethu (yesuwam@yahoo.com) on 31/10/2006, at 10:16 GMT

PSU Help.

Because of their low power ratings, zener diodes are normally operated feeding a series connected power transistor. An improved version of this is available using 7809 9v voltage regulator ic,used in place of the 7805 regulator on the layout diagram. In this case at least a 12v transformer will be required to provide the required dropout voltage headroom.

Posted by varient4121 on 28/02/2011, at 16:07 GMT

PSU Help cont.

Assuming a full wave rectifier is used the frequency of the supply is said to double (i.e. 100Hz for 50Hz input). The peak inverse voltage (of rectifier diodes) is at least double to four times (dependant on type of rectifier used) the RMS voltage of the transformer secondary winding. The average voltage depends on the load and type of smoothing used (a simple capacitor smoothing will charge up to the peak voltage output when the circuit is OFF LOAD, otherwise it will be not far above the transformers secondary voltage rating. The average current will depend on type of rectifier used (bridge type takes more current generally 1.66 to twice more)and the load. Further details in Power Supplies by R.A. Penfold.

Posted by Anonymous on 12/03/2011, at 12:23 GMT