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SWITCHES - 3 | |
V. Ryan © 2002 | |
Some common switches are shown on this information sheet. Basically switches bring contacts together in different ways but they do the same switching job. |
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Typical Switch Symbols |
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MICRO-SWITCH |
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Micro-switches can be very small. Usually they include a small arm which when pressed clicks. They are very useful and can be found on many machines - used a safety switches. For example, if the 'lid' of a drilling machine is opened to change the pulley speeds, a micro-switch is released ensuring that all power is turned off. These switches can be very useful in school projects |
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TILT SWITCH |
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One of the most common types of tilt switch uses a
‘blob’ of mercury in a small tube. When the tube is tilted the mercury
runs down and forms a bridge across the two contacts turning the switch
on. This type of switch is used in warning systems that alert people to
an excessive angle of tilt, e.g. for drivers of farm vehicles. |
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PRESSURE PAD / SWITCH |
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This is a soft flexible switch available in many sizes. It consists of two flexible conductive foil sheets separated by a thin felt, paper or foam layer. If pressure is applied the conductive surfaces touch and the switch is ‘on’ |
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