Friday, 15 May 2015

Duh… I should have thought of that!

First a thank you to Adam (nb Briar Rose) who left a comment advising the building with the white lion on top is Syon Park.  Armed with this information I did some further searching.

Syon House is the London home of the Percy family and belongs to the Duke of Northumberland.  The Duke also owns Alnwick Castle in Northumberland.  We visited Alnwick Castle on one of our UK holidays several years ago.  If I remember correctly the visit was prompted by the link to Harry Potter as Alnwick was used for some of the castle scenes in one of the films.  Syon House was buillt around 1550 but has since been extensively extended and modified.  The grounds were designed by Lancelot "Capability" Brown in the 18th century. 

We must also thank Dave for leaving a comment advising the first 24 hours mooring at Hampton Court are free.  We didn’t know that and neither was it marked on our map.  

We’ve been travelling rather fast because our youngest son has been with us and he wanted to reach Windsor.  Consequentially we haven’t been paying too much attention to the scenery.  However at one point I did look back and thought I recognised a building on the skyline.

For some reason my mind thinks this building has some connection with the Astor family?  Information Required!  In other words – Help!

The plan is to now retrace our route as far back as the River Wey.  But not until the weather improves.

The next part of this post is nerdy so if you’re not interested don’t bother to continue.

Still with me…….  OK, you may recall I made a DC to DC converter.  Initially I used it to power the laptop.  Then I converted it to run the 28” TV.  This resulted in me needing to make a 2nd converter for the laptop.  I bought a cheap printed board from China and made the second converter.  It didn’t work!  The problem was the laptop screen would brighten and then dim and the power led would illuminate and then go out.  Obviously there was a problem with the cheap chinese printed board from fleabay.  At £2.51 including postage it wasn’t worth sending back.  Instead I ordered another two printed boards.  They arrived last week and I again made up a converted using one of the boards.  I had the same problem????  Oh well, at least I had a 3rd board.  But that one wouldn’t work either.  The chances of three boards not working are rather remote and that got me thinking.  My old cheap and nasty multimeter couldn’t read amperes but it could read voltage.  The input and output voltages on all three boards was correct. 

Back to schoolboy basic electrical physics.  Watts = Volts x amps.   The laptop power brick shows input at 240V and 1.5amps = 360Watts.  The output is 19V and 3.42amps.  If I had the right volts then the problem must be the amps.  I needed to consider the 3rd factor which is the resistance.  Volts ÷ Amps = Resistance.  The amount of resistance can be equated to the diameter of a water pipe.  The smaller the pipe; the greater the resistance.  What was the difference between my first converter and this one that wasn’t working.  I realised that I’d recycled a 12V cigarette plug and cable for the output side of the converter.  On checking it I realised the cable was very long and the size of the copper wires very small.  I HAD TOO MUCH RESISTANCE.  This meant the required current couldn’t reach the laptop.  Today I replaced the long curly cord cable with some thicker and shorter cable.  The converter is now working as expected.  A very simple mistake and I should kick myself for not recognising the reason for the fault.

Now I have two spare DC to DC printed circuit boards. No doubt they will come in useful at some future date.


Adam said...

Star and Garter home for disabled servicemen.

Paul and El said...

Well I could have told you that.............not!
I changed a lighbulb yesterday, that's about as far as I go with electrickery