Today in the developed world we accept our utility services without a second thought. Electric is just there, available as a stable (well, relatively!) supply whenever we want it. It was a very different matter a hundred years ago. Here in the UK domestic use was originally very limited until local authorities used an assisted wiring scheme to encouraged people to connect their houses. To quote a line from the History of public supply in the UK:
"The scheme began in 1930, and by 1936 over 12,000 premises had been connected"
(Photo: John Thorpe)
All this played havoc with Meccano's plans to introduce the new technology to their system. While all this was going on Meccano introduced a lighting kit to add lighting to their models. The bulbs supplied were small grain-of-wheat (GOW) style filament bulbs. Today any of these bulbs that still exist are precious and although will probably still work today, they have a relatively short life expectancy and using them in our models for every-day use is not something most of us would want to do. In order that Sue could use her table lamp from her lighting kit (that I would not dare hint we use!), I suggested we used a modern alternative, instead of a modern replacement GOW bulb.
|Sue's lighting kit|
|This is its normal state - closed!|
Light Emitting Diodes are not new and have been with us for decades. it is only in recent years that the technology has moved on to produce useful colours and at a price that is affordable. They have several other advantages including developing hardly any heat and just sip power so they will run on very little supply current, usually 20mA. I won't bore you with the maths but it is very easy to match a led to any low voltage supply just by adding a current limiting resister in series with the LED - they also have to be connected up the correct way to a DC supply. If you want more detailed information on using LEDs, and the formula to work out what value of resister to use for a given supply voltage, go to THIS post on my workshop blog - you will have to scroll down a bit, past the frog - you'll see! For now, if you want to run a standard brightness LED from a 12V supply you will need a 470 Ohm ¼W resister.
Sue's LampSue wanted to used her table lamp from the lighting kit but did not want to use the original lamps for fear of damaging them so we came up with a modern solution to the problem!
|Old meets new|
|Parts required - you only need one resistor!|
|Resistor soldered in place|
|Heat-shrink tube insulation - great stuff!|
|The leads emerge from the base and are twisted together.|