Here's a simple DC power supply having three output terminals: regulated +5VDC, unregulated +10VDC and 7.5VAC. The supply is suitable for microcontroller experimenting for any student.
My workbench has many broken devices and most of them will be used as the part for making the electronic projects. One day I looked at the broken radio, I found there's an AC line cord with socket and a transformer. Actually I like the way they used AC socket with the AC cord. I thought why don't make a simple DC supply from these parts. Most of the DC adapters provide only DC output. But not AC output, some of the uC circuit need a +5V for digital circuit, some need an AC line voltage for timing synchronization, digitizing sine wave, and some need unregulated for relay driving. So I designed above circuit for lab usage.
The DC power supply circuit is a linear regulator providing galvanic isolation from main line through the use of isolation transformer. Quite safe for experimenting with AC voltage. Below pictures show the example of input/output terminal connections, labeling and components placement in the box. The circuit can be built using universal PCB. The output terminal is for big load connection so this makes it quite strong and good electrical contact to the load being used.
Simple DC Power Supply for Students
