You can use this power supply for your electronics project which only require electric current about 500mA. This is cheap circuit which will give you stabilized output voltage.
If you want to change the output voltage, you should change the IC type.
For example, you need 5V output, then change the IC from 7098 with 7805 dan change the output of transformer from 16V AC become 9VAC or 12V AC.
Watch the video: