Monday, March 11, 2013

Using Cell Phone Charger For Making a LED Tube Light

A plug in wall lamp can be built at home by using a few white LEDs and by powering it through a cell phone charger. The power from cell phone charger is around 6 volts at 500 mA approximately. The power may be well suited and can be tried for powering white LED lights. The application includes some important types like a LED tube light, LED wall lamp, LED porch light, LED table lamp etc. to name a few.

A discarded, spare cell phone charger and a few inexpensive LEDs are all that you want you make a simple yet powerful LED tube light. The cell phone charger can also be used for making a porch light, a bed room wall light or a table lamp. Full circuit schematic is enclosed here in.

A nice little wall mounted cool lamp can be built using a few number of white LEDs and s discarded AC mobile charger adapter. The use of a cell phone charger makes the entire unit very compact and perfectly mountable on wall sockets.
Cell phone chargers are not new to us and nowadays we all seem to have a couple of in spare with us. This may be mainly due to the reason that whenever a new cell phone is procured a charger comes free within the package with the handset. This units are so long-lasting and rugged that most of the time chargers last more than the cell phones.
These spare cell phone chargers often lie idle and at some point of time we tend to dispose them off or simply discard them from our house. For a lay man these units may be a piece of junk, but a technical individual might make a complete gem out of it. Especially a person who may be an electronic hobbyist will very well know how valuable a cell phone charger can be even when it’s not being used for its actual intended purpose.

What are Cell Phone Chargers and How do they Function

We all have seen a cell phone charger working or rather being used for charging cell phones. Therefore we definitely know that it’s something to do with the supplying of some sort of power output.
That’s correct, these are actually a form of AC to DC adapters, however they are incredibly efficient as compared to an ordinary adapter which may employ a transformer for the required conversions.
Cell phone chargers are able to provide a nice six volts at a massive 800 mA of current. That’s quite big considering the size and the weight of these units.
Basically a cell phone charger is a high-grade SMPS power supply at the above rated level. Fortunately a white LED also works at potentials which quite matches with the above specs.
This prompted me to think of using a spare cell phone charger to be used as a plug-in type wall lamp. Mind you one charger can provide enough power to support at least 30 odd numbers of high power high-efficiency white LEDs. It simply means that the lights can be used as a compact LED tube light which can comfortably replace a common CFL light and generate light quite as good.
At no loads, a cell phone charger may provide outputs up to 10 volts, which can easily power a couple of LEDs in series. The series will consume a minimum of 20 mA, however since the charger can supply a good 500 ma plus current we can add 15 more such series in parallel, making the total accommodation close to 30 or more LEDs.

Parts Required

You will require the following parts for constructing the proposed project:

Series Resistors - All 68 Ohms, 1/4 Watt

An ordinary spare cell phone charger – 1no.

White LEDs – 30 nos. for making a small tube light or 10 LEDs for making a wall mounted bedroom lamp etc. (see text)

PCB – General purpose type or as per the project specifications.

Construction Clues

Constructing this LED wall lamp is not difficult as it only requires the LEDs to be fixed in rows and columns correctly as shown in the diagram. You may use the power from the cell phone to light any number if LEDs depending upon the requirement.
For example if you want to make a porch light for illuminating your house veranda, then probably you would need to assemble not more than 6 LEDs.

For making a cool bedroom room lamp a single LED would suffice, instead of sitting in complete darkness, this light may be used or switched ON while watching TVs or videos.
For making a table lamp for reading purposes, a group of 10 LEDs would provide enough light for the purpose. 

And as discussed above, a descent LED tube light can also be built by assembling some 30 + LEDs in conjunction with a cell phone charger power supply. 

For all the above applications, the basic mode of soldering and fixing the LEDs remains the same. Fix and solder a series of two LEDs with a series current limiting resister and now go on repeating this series as many times as you want, depending upon the type of lamp you are trying to build. Once you finish assembling this layout, you may go joining all the free ends of the resistors which becomes one of the supply terminals, similarly join all the remaining free ends of the LEDs, which becomes the other supply terminal of the unit. These supply inputs now just needs to be connected with the cell phone charger supply.
The LEDs should immediately come ON and produce illumination just as desired by you.
The assembly now needs to be housed appropriately inside a suitable plastic enclosure as per individual specification and liking.

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