Most electronic circuits need
a DC supply such as a battery to power them
and the main supply is AC it has to be converted
to DC to be useful in electronics. This is
what a power supply transformer does. First
the AC mains supply passes through an isolating
switch and safety fuse before it enters the
power supply transformerunit.
In most cases the high voltage mains supply
is too high for the electronic circuitry.
It is therefore stepped down to a lower value
by means of a power supply transformer.
The mains voltage can be stepped up where
high DC voltages are required by a power supply
transformer.
From the power supply transformer the AC
voltage is fed to a rectifier circuit consisting
of one or more diodes. The rectifier converts
AC voltage to DC voltage. The power supply
transformer is essential to this process.
