Houston We Have a Problem 122, 18/09/10
just bought a new laptop with a Lithium-Ion battery pack. It will be used at
home, plugged into the mains, for 90 percent of the time. I have seen conflicting
views on websites as to whether the battery should be removed or left on board
in these circumstances. What is your
Smith, by email
Personally I would leave the battery in place. It won’t make much
difference to the battery’s life expectancy as virtually all chargers are
designed to stop charging once the pack has reached 100 percent capacity.
Improvements are in the pipeline but the majority of Lithium Ion batteries
degrade from the day they are made and their ability to hold a charge drops by
as much as 30 percent after only two years. Battery packs typically last 3 to 5
years, whether or not they are being used, but by that time many laptops have
developed expensive faults, run out of disc space or been replaced. But even if a laptop is used extensively on
battery power, most battery packs can only withstand 300 – 500 full
charge/discharge cycles. Incidentally, these are all good reasons not to buy a
spare pack, unless you are going to use it.
Nevertheless there are a few simple things that you can do to
improve your battery’s chances of lasting the course. The first one is to
regularly run the battery down to the point where you start seeing warning
messages about only having a few minutes of power left and to save your work. Doing
this every two or three weeks gives the cells in the battery some exercise and
can help to keep them in good condition. Avoid high temperatures; leaving your
laptop in a car on a sunny day, for example is a bad idea. Also stop your
laptop overheating by making sure that the fan exhaust and air vents are
unobstructed. Finally, don’t let the battery run flat. If you are not going to
use your PC for a while – several weeks say -- fully charge the battery then
remove it from the machine. One last thought leaving the battery pack in place
could prevent data loss in the event of a power cut as it acts like an
uninterruptible power supply.
Could you tell me how to convert files created in Microsoft
Publisher and Corel Draw into PDF format? I use these programs at various times
and need to send my work to a commercial printer. They always ask for files in
PDF but it’s not listed on any of my program’s 'Save As' menus.
Ron Holmes, by email
PDF or portable document format was developed by Adobe as a
means of viewing and exchanging illustrated documents over the web and on a
wide range of devices that use different applications and operating systems.
It’s a proprietary format, distantly related to PostScript (also from Adobe, a
powerful industry standard page description language used in the printing and
publishing industry). Until fairly recently the only easy way to create pdfs
was to install a commercial program called Adobe Acrobat but now there are a
number of freeware alternatives, including PDFCreator (http://tinyurl.com/3xqbgwe). However, you
won’t find pdf on the Save As menu. Instead go to the Print menu on your chosen
application where PDF Creator shows up on the list of installed printers;
simply send the document you want to turn into a pdf to this virtual printer.
Don’t Trip Up Buying a Laptop
On my many trips to USA I am tempted to buy my first laptop
for use there and at home. Are there
any pitfalls to consider before doing this I wonder?
Albert Hill, by email
Yes, and my first and only piece of advice is don’t do it!
It is unlikely you will save any money; these days US prices are not
significantly lower than the UK. There’s a chance it will cost you even more
than you expected if upon your return Her Majesty’s Customs and Excise decide
that you need to pay VAT and import duty. It will almost certainly have a US
keyboard, so you’ll have to fiddle around if you want to use the £ and @ signs
and it’s a very long way to go if, for any reason, you need to take it back to
Raising the Bar
How can I get a bar or a dot over a digit in order to
indicate a recurring figure?
Joseph B. Fox, by email
It sounds like a simple enough request but in fact this is
quite difficult to achieve; it also depends which word processor or application
you are using. If you are using Word my preferred method is to type the two
characters (i.e. 2 _ or 2 .) highlight the dot or bar and use the character
spacing controls on the Format >
Font menu to raise the dot or bar above the character using the Position
control (typically by the font size, so if you are using 10 pt characters,
raise the dot or bar by 10pt). Next, highlight both characters and use the
Spacing control to condense the dot or bar and character; try 3pt on a 10 pt
character. The only problem with this technique is that the hybrid character
increases the spacing on the line it is on. If this is a problem your best bet
is to use Word’s Field Code or Equation Editor methods and there’s a reasonably
easy to follow tutorial at: http://tinyurl.com/2um9f8g.
my new mobile phone, PC and Sky+ box completely locked up. The only way I could
find to get them working again was to unplug and reconnect the PC, take the
battery out of the phone and wait for an engineer to come and fix the Sky box.
What causes this to happen?
Mulley, by email
almost certainly just a coincidence and you have just been unlucky. All of the
devices you mention use microprocessors – much like the one in your PC -- and
when there’s a glitch in a program or operating system it freezes. Temporarily
removing the power reboots the system and all is usually well once again,
though it sounds as though there may have been a more serious fault with the
thing I can think of that might make it happen on three devices at the same
time is a surge or ‘spike’ on the mains supply (assuming the phone was plugged
into its charger, or the PC). These can be caused by nearby lighting strikes,
line switching at the power station or substation and occasionally, by large
appliances in the home, such as central heating systems and freezers switching
on and off.
Maybury 2010 2108