A321 Electrics DC
 

I seem to have a mental block. Am I correct in thinking that the DC / battery system is PURELY there to supply electrics to the AC Essential bus via the battery and static inverter??? In normal operation, AC via the transformer rectifiers and hot battery bus is charging the batteries in case it all goes wrong. Have I got this completely wrong? Is anything actually powered from DC in a "normal" operation?

Yes, hundreds of things are powered by DC. Hence one reason why you can fly on batteries only.

Much too long a list to reproduce here.

Check the FCOM

Also have a look in the QRH at the landing distance with a DC bus failure.........

A320 transponder
 

I do jave a big question about A320 transponder .. someone please help me..
Among VHF and TCAS antenna wich antenna is use to transmit transponder info from the aircraft that can be received by a Secondary Surveillance Radar or by an ADS-B receiver?

Regards,
Skywalker92

Why would a VHF or TCAS antenna be used to transmit transponder information???

Surely it would be the transponder antenna!