on an AVT TV Tuner (and I think pati din sa standard na mga stereos sa vehicles), the electrical diagram (sa power supply) consist of GND, +12V, ACC...

the GND and +12V - sa pagkaintindi ko serve as the main supply....

but the ACC? para san to? kung may GND and +12V na, mag on na sya di ba?

or is it pag +12V and GND lang ay laging ON na yung appliance (in this case TV Tuner) and it is the ACC that triggers On and Off (bukod pa shempre mismo sa On / Off switch ng pinaka unit)?

Tama po ba?