Devices switch power

To or from the electrical pathway

One reason why there are a lot of electrical circuits about is that we're good at designing devices that switch from the electrical pathway.

There are other devices …

We're also good at designing devices that switch to electrical power, for circuits that don't rely on batteries, like the mains.

There are other devices …

A general pattern

These four examples are

But why?

You can't manage a process where there is more output power than input power: a device can only divide up what's available. The device only switches power amongst pathways. If it switches most power to a pathway you want (a target) then its a good device: if not, time for a redesign.

Power descriptions check where a process is possible, and guide ways to improve the process.