Saturday, 29 March 2014

How To Convert Fluorescent starter to Thermal Switch

Fire Alarm circuit by using reject starter of fluorescent tube light  

Picture of How To Convert Fluorescent starter to Thermal Switch
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Fluorescent starter is essentially two bimetallic strips in a sealed glass capsule, with a small gap between them.

The principle of this experiment is Metal expansion and contraction.

Materials:
1-  12 volt CPU Fan.
2- 12 Volt supply.
3-   Fluorescent starter.
4- Candle.

Steps:
1- Break the starter glass and try to not damage the metal inside (Take all safety precaution when you do that to avoid any injury).
2- Make sure that there is a small gap between two metal as shown in attached picture.
3- Connect the circuit as attached in the first circuit diagram and fix the starter about 2 cm above the candle.


When the candle lighted up, the starter metal will expand and attached together, the fan will turn on and turn off the candle ,the two metal will de-attach and turn off the fan.

Note that CPU fan is a brush less dc motor and it will not cause spark in starting, the spark can damage the metal and it will not work for long time, so if you connect a load that take more current and cause a spark in the starter you can use transistor showed in the last diagram to avoid this issue.
When you just change this fan and connect a buzzer device . now this is a fire alarm device .


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