Here is a 5V 5a power supply circuit using LM7805 IC. LM7805 is a 5V fixed voltage regulator IC with the max output current of 1.5A, but by using a transistor you can increase the output current of this IC easily. The 5V power supply circuit shown here is using a TIP2955 transistor to increase the
output current of the LM7805 IC up to 5 ampere, you can also use other similar transistor in the place of TIP2955. The transformer can be a 230V or 110 V AC to 12V 5A type. The transistor will heat up during the circuit operation therefore use a suitable heatsink with it.