Another question

[Paddypix]

This is just out of curiosity and I wondered if WM or Suff could explain. I've just been putting the cable away after charging my netbook and I was going to cut off and dispose of a piece of paper attached to the cable. I read it first, and this is what it says, among various safety warnings: "the flexible cord of this accessory must be connected to a piece of equipment before being plugged into a socket-outlet". Is this important? It has never occurred to me to attach the cord to the netbook before plugging it into the wall. Sometimes I do and sometimes I don't as I didn't know it mattered. Same with my laptop.

[Workingman]

The issue is 'surge' and it is not easy to explain, but I'll try.

The cable from a UK house supply is carrying 240 volts AC. It attaches to a transformer which converts the supply to xyz volts DC. The transformer then supplies the Netbook/Laptop/Tablet at the correct DC volt supply.

If everything is connected as a continuous circuit when the cable is plugged into the wall socket the AC/DC and voltage conversions will have been done. However the Netbook/Laptop/Tablet does not have to be connected at this time.

The main problem occurs when attaching a 'live' 240 volt AC cable to the DC transformer and the rest of the circuit. This creates a 'shock' to the system and could damage the transformer and any equipment down the line at the DC outlet.

Best practice. Attach all cables - end to end - before plugging into and switching on the AC supply, then plug in the laptop.

In the UK we can turn the wall socket on/off so we can do this in stages before turning 'on', this is not always available in Europe, the US and other parts of the world.

[Paddypix]

Thanks WM. I'll be more careful in future.

[Suff]

Just to add here that the smaller and lighter the power supply, the less protection it has from surges. So, the way they get around that is to use the machine itself, as WM says in circuit, to protect against the shock.

I never plug the machine in first for the simple reason that if there is a problem it's likely that it will kill the adapter but not the device. I'd rather the adapter blew up than my laptop. But they have to say this to make sure it's all "safe" even if it doesn't make financial sense to you.

[Diflower]

It was only when we got the galaxy that I spotted the instruction, it said it was important that you always connect the cable first to the gadget then the socket. Then when I got the mp3 player it said the same thing, so although I had no idea why I assumed it must matter