There are two ways to rectify ac current to dc. One is half wave rectifier another full wave rectifier. In full wave rectifier we need 4 diodes to convert ac to dc , but in half wave rectifier only two diodes are needed. So if we need 12 volt dc from a transformer we split the secondary coil as 12-0-12 instead of 0-12, the middle tapping is called as 0 and two extreme tappings are 12 volt each. Now by using two diodes for rectification to get 12 volt dc. This also improves power output current. On other hand we can use a 0-12 volt output coil plus a full wave rectifier to get 12 v dc out put.
Thank you am also fine like you then dear generally 12 v – 0 v – 12 v is secondary of centre tap transformer & so primary of transformer be asked may 230v / 110v / etc.
it means it is of 24v
12 on one side and 12 on another
I THINK THE TRANSFORMER YOU HAVE BOUGHT IS PROBABLY A CENTRE TAPPED TRANSFORMER. WITH TERMINAL 1 AT +12V TERMINAL 2 AT 0V TERMINAL 3 AT -12V. SO, IF YOU CONNECT THE 1ST AND 3RD TERMINAL YOU GET 24V IF YOU CONNECT WITH 2ND TERMINAL AND ANY OF THE OUTER TERMINALS YOU GET 12V.
12V input voltage
0 volts across nuetral or earth
12V output voltage.