Editor's Note: Here's another take on the transformerless AC line power supply, which finds use in some well-insulated, low-power devices. Our technical reviewer pointed out that C ac should be an ...

This AC power switch circuit senses the presence of AC current in one outlet of a multi-outlet power strip and switches power to the remaining outlet(s). It utilizes a current transformer, single ...

Calculations of power and energy are relatively straightforward when the subject is strictly dc circuits. The situation is more complex in the ac world, however. Here are the basics of watts and ...