LED Tube light Repairing. Home Utility Circuit 32

1ALED Tube lights are costly lights but susceptible to instant damage. Since it uses an LED Driver and very sensitive LED Chips, voltage fluctuations, voltage surge, over heating etc can destroy it easily. But all the parts of the LED Tube light will not fail, so that we can easily repair it. The major problem may be the failure of one or more LED chips or the driver. By doing some repair works, we can use the LED Tube light again. I found one of my 12 Watts LED Tube light is not glowing and decided to repair it. Now it is working well. Its expense was just Rs.50 for the driver only. See the step wise method of LED Tube light repairing.
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USB Light. Home Utility Circuit 30

Harvest energy from the USB port of your Laptop or PC to light an LED lamp. It is useful as an Emergency lamp in the event of a power failure or it can help you to use the Key pad in night without disturbing the sleep of others. It is too simple and easy to make it. The USB.2 .0 port available in all laptops and PC gives 5 Volt DC and 200-300 milli ampere current. It is enough to light a High power 1  watt LED. Just plug the light in the USB port and enjoy its light. Cool! it is good enough to read a book also. In the market its costs Rs. 300 and you can make it for just Rs.10.
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Car Light. Home Utility Circuit 28

8AThis is a simple 10 Watts LED light you can easily make. It will help you to check the engine, battery terminals or other parts of Car during night. It will act as an efficient high intensity Torch light. It is also useful to check the inverter and its battery usually placed in low light areas. By hooking the clips in the battery, the light will turn on. If you fix a Magnet with it, you can stick the lamp to the vehicle’s body so that your hands will be free to do work. Let us make it. Its cost is Rs.50 only.
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Relay for LED Emergency Light. Home Utility Circuit 26

1AWhy going for a complex circuit to make an Emergency Light automatic? Now different types of low cost Portable LED Emergency lights are available but these are not automatic in function. A Mobile charger like adapter is supplied along with these for charging. But we have to turn on / off the light manually using the switch. We can easily convert these kinds of Emergency lights into automatic so that when the power fails, the light turns on and when the power resumes, it turns off and enter into charging mode. We need only one relay and a diode for this. The advantage of the relay is that, full current will flow to the LED panel to get maximum brightness.
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LED Panel Emergency Lamp. Home Utility Circuit 21


You can make an LED Emergency lamp easily using the LED Panel available now. The lamp turns on when the power fails and turns off when the power resumes. When the mains power is available, the 12 V 7.5 Ah battery charges. Since LED panel is used, the emergency light can have a back up time of many hours. You can make 9 Watt or 18 Watt Emergency lamp using the circuit presented here.Its Backup time will be 10 Hours.Its cost will be around Rs. 950. Of these, the battery alone costs Rs.800. If properly maintained, the battery will last more than 4 years.

Designed and developed by D.Mohankumar

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Bread board power supply. Home Utility Circuit.16

1AThis Project is for the Circuit designers. Lot of projects are experimented in Bread board and Perf boards before finalising the project. So these projects need a power supply to test. Usually a 9V PP3 battery is used to power the bread board. So here is a compact Portable Power supply unit for the Bread board experiments. The Power supply includes
1. A charger indicator for the 9V rechargeable battery
2. A battery voltage monitor
3. Output sockets for charging and tapping power to bread board.
4. An LED light for the bread board working
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USB Light. Simple Design 6


You can make a simple LED light to read and type in Computer or Laptop during night without disturbing other’s sleep. It is also useful as a mini Emergency light in the event of a power failure. It is too simple and powered from the USB port. USB lights are available in the market, but costs around Rs.150. You can make this USB light at the cost of just Rs.5.
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