A system that converts AC current from the wall outlet into the DC currents required by electronic circuits. A computer power supply converts ... supplies known as "switching" power supplies ...

For one-off projects or prototyping, it’s not too hard to find a wall wart or power supply to send a few joules of energy from the wall outlet to ... timer to build a switching power supply.

Use a wall outlet ... enough power to display the lightning bolt that indicates it is charging. Use the iPad charging block ...