is it true that electoronical device are still alive even when they are off? if yes why?
It depends upon the device. The recent generations of computers have a standby voltage which is always on, many TVs and other electronic devices have a similar feature. This allows for soft on/off switches. That means the device is controlled by lower voltages and usually comes up faster.
If you pull the plug they are off cold.
Again this feature depends completely on the device and varies.
Yes, it is true.
Devices that are not completely off can:
- respond to a remote control
- keep time
There's also the factor that even something like a toaster draws an infinitesimal current when not in use, if plugged in, just because most on/off switches aren't perfect insulators.
If a person is going to THAT extreme I'd say leakage in the cord and for that matter the wiring in the house is more significant.
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