This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall adapter with variable output voltage are available from any electronics shop and supermarket. Those adapters are easily available, but usually their voltage regulation is very poor, which makes them not very usable for digital circuit experimenter unless a better regulation can be achieved in some way. The following circuit is the answer to the problem
This circuit can give +5V output at about 150 mA current, but it can be increased to 1A when good cooling is added to 7805 regulator chip. The circuit has over overload and thermal protection.
I have just made one which you see in the picture above where I have added two header pins so that it can be easily plugged onto a solderless breadboard.
fine thanks