Electronics in the UK
9 December 2011
General
Electric devices made for the American market can be used in the UK as well as other countries, but caution should be taken. Different counties may use a different voltage (volts) and/or frequency, known as cycles expressed in hertz. The plug you use at home may not fit the outlet in other countries. You will need to use an adaptor or specific plug for that country. To see all the plug types in the world, go to Yung Li and further illustrated in this org site. You can enjoy Europe more by reading this enjoyable site.
Batteries
Recharging Batteries
Some hotels have battery-charging towers in the lobby for cell phones. Cell phones are called mobiles the UK. You place your phone into a compartment with the connector that fits your phone; drop coins in a slot and lock and go. Yes, it costs and you are without a phone for a while (talk a walk) but if you are without a charger it can be worth the money.
Batteries on Aircraft
As of January 1, 2008, lithium batteries are not permitted in checked luggage unless installed in a device. Spare lithium batteries can be brought thru in your carry-on bag. The concern with these in checked bags is that they could short out and cause a fire. A major US electronics retailer had old batteries in a glass container on the counter for customer drop-off. They didn’t play well together and a heated fire broke out burning down the store. See the TSA website for this and more up-dates.
Dual Voltage Devices
America uses 120 volt, AC (60 Hz) current. The UK (England, Scotland, Wales & all of Ireland) uses 230 (European Commission mandated) AC (50 Hz) current. If a device has an allowable input range between 110 and 240 volts and 50/60 Hz, it is a dual voltage device and no converter/transformer is needed. Laptop Travel has a bit more to say on this.
DVD’s
DVD disks have codes that only allow it to be played in a certain region, as described here. Be aware that DVD’s and Blu-ray disks may not play on your player if purchased overseas if not coded properly.
Electronic Stores in London
Apple Store on Regent Street W1 & Covent Garden WC2
Maplin has stores in several London locations as well as across the UK
Hotel Electrical Outlets
Hotels may have outlets for US electric razors and hair dryers, but caution should be used. Electrical outlets in bathrooms may not be protected by a ground-fault-circuit-interrupter (GFCI). These plugs have a reset button in the middle and if you are not sure ask the hotel staff. They are made to prevent death by electrocution (the outlet that is) by disconnecting the power in milliseconds. Caution should always be observed when using power devices in a bathroom.
Electrical outlets in some if not all hotels have a switch built into them so if it does not seem to be working set it so that the red mark is visible. Also, in my hotel, the telly can be turned on/off by a bedside wall switch. Check these things before you call the porter. In addition, some plugs for things like lamps have a built-in fuse as shown in the MAC photo below. The port on the left is a DSL connection.
Photo of smart phone connected to 230 volt power outlet
Photo of DSL cable connection
Note: I have never used a converter with an adaptor for an electronic device. Talk to an electronic technician about this. What makes laptops different between the US and UK is the AC adapter. You may want to buy one for the UK system before you go to play it safe.
MAC/Apple Devices
The photo below shows plugs for MAC devices for use in the UK. 
The plug on the left is a USB plug for use in the UK. It has an input range between 100 to 240 volts AC for 50 to 60 hertz. Output is 5 volts DC at 1 AMP. I bought this one at the Apple store in London for use with my iPhone. It came with a USB chord that fits the iPhone or similar devices.
In the middle is the plug for use in the UK. It is a 2.5 AMP, 250 volt AC – 50 hertz plug with a fuse (shown removed) built in. This fits on the power adaptor (right) that came with my laptop. Connecting the plug to the adaptor will allow you to use your device in the UK. Unfortunately the USB cable for the MAC laptop is different from the one used by the phone.
PC Devices
PC devices can be used in the UK with proper plugs that are similar to that shown in the photo shown below. The difference is how they accept your device. The photo below shows a UK plug for use with a HP iPaq handheld. The plug doesn’t plug directly into the device but rather a fitting that came with the device. 