power transformer questions

[simonwai999]

hi folks
in my city we use 220vac
i have a power transformer
220 primary and 9-0-9 secondary
all i need is 9vdc
can i connected (9-0)-9 the 2 pins in the bracket to get 9vac then rectify it
to 9vDC for the 7805 ic?
thanks

 

[kiprono]

You are right. Your transformer has a centre - tapped secondary.

 

[tonybg]

yes, you can get DC from the secondary coil.But it is a little bit different.Use the 0 for (-) on the DC side.Then on the two 9Vac ends connect two diodes-anode to the AC side and cathode to DC side(connected together). Don't forget the electrolitic capacitor.You will measure DC voltage more than 9volts.But you will need at least 2volts difference inorder for 7805 to stabilize.Be careful what current you draw from 7805.If it is more than 200mA use aluminium plate to cool the device.Don't forget
HELPED ME!

 

[simonwai999]

hi
thanks for your fast reply

ciao