Time reminder.Design Trick 9

This simple transistorized timer can be used to remind an activity such as telephone use, heater on, pump on etc. It beeps at an interval of one minute to remind the activity. The circuit is too simple and can be assembled in 10 minutes.
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Timer for Charger

Some Microcontroller based Laboratory instruments such as Digital balance, pH Meter etc have rechargeable battery inside. This inbuilt battery should be properly charged for the error free operation of these instruments. If the instrument is not using (or charging) for long time, its inbuilt battery will be destroyed permanently. This timer circuit helps to keep the battery in top condition through automatic charging for 5 to 6 hours daily so that the instrument can be left unattended. The battery will be charged only during the day time.

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Timer for Mosquito Destroyer

This is my circuit published in Electronics for You Magazine March 2010 issue.I have designed this circuit to reduce the inhalation of toxic chemicals from the liquid vaporizer. The timer action of the circuit switches On /Off the vaporizer at an interval of 15 minutes.This reduces the quantity of chemicals in the air and increases the usage time of the liquid.Full circuit is given as image .

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