Electrickery 2

[The Medway Handyman]

Recently bought some of those remote control sockets so we can turn table lamps on/off.

There I was, in the kitchen, trying to work out which button controlled which socket.

The nearest handy item to plug in was a large wall wart with an LED indicator.

Plugged that into one remote socket & tried the buttons, number 2 triggered it & the LED came on.

Pressed the number 2 'off button, heard a click, but the LED stayed on.

Plugged wall wart into phone, no charging.

How come the LED stayed on?

[Andy Burns]

Capacitor in the PSU, has enough juice to run the LED for a few seconds, but not enough to run anything useful like the phone.

[John Rumm]

Capacitors in the power supply - will hold enough charge to light an LED for some time.