Mains Failure Alarm
Approx construction cost US$13
Protect your freezer or fish tank contents, or monitor mains connections.
Mains failure alarms are often employed in situations where the removal of the mains supply from a piece of equipment can have adverse or even disastrous consequences. In the domestic situation, the equipment in question could be the freezer, which, in the event of a mains failure, could result in large amounts of food thawing out and having to be thrown away. A tank full of expensive tropical fish may be another example, while at school or in a laboratory the failure of the mains supply may result in a long-term experiment having to be repeated.
Very often, the "failure" may simply be the result of the switch on the outlet socket being operated inadvertently and this may have no immediately noticeable effect on the equipment. The results of the mistake may only become evident a few hours or even days later, when it is too late.
More details on this construction project can be found in the December 2001 issue of EPE Online, the world's first web-delivered electronics and computing hobbyist magazine.
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