Changing A Mains Isolation Switch Neon Indicator


You may notice how the indicator light in your mains sockets and switches dims with time and wonder why. These lights are usually small neon bulbs which glow when a small alternating current of 1 or 2mA passes through them. These bulbs are filled with neon gas which glows red when a current passes through it. There is no filament and no heating element. Neon is an inert gas which glows with an orangey red colour in these bulbs. If the current is too high or the electrodes are made of an unsuitable metal the metal evaporates from the surface of the electrodes and condenses on the inside of the glass bulb, making it opaque, so the light output dims as the glass gets covered.

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Changing a Watch Battery


My wife’s wrist watch stopped working the other day. Usual problem – flat battery. So I popped onto the Internet and ordered four, from JewelleryForAll on the Amazon Marketplace, @ 45p each with free p+p. They arrived on 14th Jan 2012. A little late I thought since they were ordered on 3rd Jan 2012, but never mind they were cheap enough.

The Battery I Ordered

The new watch battery came in a package like this: Packaged Cell

When extracted it looks like this on the +ve side, the side which faces up in the watch. The colour is of course silver but this image allows the engraved text to be seen: +ve side of cell

This shows the -ve side, the side which faces down in the watch: -ve side of cell
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Gyroscopes & Cameras Help Bike Riding Robots

Watch This Video of Bike Riding Robots

Watch Murata Girl and Murata Boy. They use stabilizing gyroscopes and camera technology. These are bike riding robots which perform some amazing riding skills without falling off their bikes. Murata Girl is the one on the monocycle.