switched off/on-elec

[tali122]

if an electrical appliance is switched off but the switch is on at the mains - is electricity being used?

[Buenchico]

Electricity is the flow of electrons. If the circuit is broken (by the switch on the appliance being 'off') there can be no flow, so no electricity is used.

The previous paragraph assumes, of course, that the appliance is genuinely 'off'. Most PCs, for example, which have been 'shut down' aren't genuinely switched off. (To do this you have to use the switch which is usually located on the back of the cabinet). A 'shut down' PC is often actually in a form of 'standby' mode and is therefore using a small amount of electricity. (Although the amount is small, it's been estimated that the UK could shut down at least one power station if everyone always switched off their PCs - using the rear switch - rather than just shutting them down).

Chris

[buildersmate]

Not necessarily true, I'm afraid Tab. Different power stations work in different ways. The nuclear powered ones work as a baseload power generators and what you say is true about them. They are planned to be 'on' all the time except during maintenance. Smaller gas turbine stations are used to provide short term injection of power into the Grid and they can be run up and then run down again in a few tens of minutes. But the unit cost of the electricity they generate is higher (to the Supplier companies - not to the end user).