Night Active Relay. Utility Gadgets .13


Now you can light your home premises with this Automatic lamp. It turns on in the evening and turns off in the morning. No switch and no manual operation. So it can light the premises even if the inmates are not in home. A simple security measure.

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Over Voltage Protector. Utility Gadgets .12


Protect your LCD TV from Over voltage. After a power failure or during lightening, very high voltage surge develops in the Mains line which is the major cause that damage TV. Plasma and LCD TV are costly devices and uses SMPS type power supply. Use of Stabilizer is recommended for LCD TV. This low cost circuit can do the job of protection very well. When the mains voltage increases above 250 volts, it will drop most of the voltage around 100 volts passing through the load and the condition remains as such till normal voltage level attains.

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AC-DC Emergency Lamp. Utility Gadgets.11



Once I purchased a China make AC-DC LED emergency lamp for Rs.70. I wonder ,how they are selling the device cheaply. Due to curiosity, I opened the case of thelamp. So simple circuit that cost only Rs.20, a small 6 volt battery and LEDs. This is the reason why they are selling the device at low cost. Reliability? Sometimes it will last years, otherwise few days. That depends on the use and conditions. Most of the China make devices use tranformerless power supply which can damage when spikes appear in the mains lines. Any way, simplicity and low cost can be considered. I have drawn the diagram and constructed one sample. It is still working. Let us see the circuit.

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