*LED Light Bulb*
By Justme

Make an LED bulb that can be carried and used in a standard 2 cell (3volt) flashlight. I use this while camping or reading in bed.

Here is a light that can be could used to read at night without destroying night vision or being so bright as to disturb the person trying to sleep next to you. Using a regular bulb with red filter works but batteries won’t last very long. Batteries will last almost forever using the LED bulb and the bulb can be swapped out for a standard bulb if necessary. The goal here is the ability to use any small flashlight using 2 AA cells or any military 2 cell flashlight.

I know that some people may want to use a blue or green bulb but I prefer the red bulb. This is what is used on aircraft and no red markings are used which may disappear in the glow of a red bulb. You decide what color suits you best.

I tested blue and red Radio Shack LED’s for use.

Blue: stock # 276-311. Listed at 5 volt with a maximum 6 volt. Best with 3 batteries. Using 2 batteries this LED is very dim but can be used to read at 1-2 inches. The bulb is plenty bright for use as a signal light.

Using 3 batteries (4.5 volts) the LED is bright enough to read at about 12 inches. There is enough light see at your feet or dimly at about 10 feet away. Using 4 batteries the LED dims and will blow soon.

Red: Stock # 276-018A. The best glow for reading. High brightness LED with holder (2 in package). Listed at 2.1 volts, 10mA.

Works best with 2 batteries. Dims and is ready to blow with 3 batteries. This LED gives a good even glow with plenty of light to read at about 12 inches. The light diminishes quickly with just a dim glow at your feet and at about 10 feet in a dark room.

Red: Stock # 276-307. The brightest and good for reading, I like this one best. Listed at 1.7 volts but runs well at 3 volts (2 batteries). Still going after 10 hours of use. Will dim and blow out at 4.5 volts (3 batteries). This LED has light and dark areas like a regular bulb but can still be used for reading. It shows plenty of light at your feet and glows bright enough to make out objects 10-20 feet away in a dark room. It is a very bright signal light.

If you prefer other colors, Radio Shack has LED’s that will run at different voltages and brightness levels. Experiment to find the best one for you.

Making the bulb

Use eye protection to protect against broken glass

Break out glass with pliers and use an awl to poke through bottom glass to gain access to solder -ball at bottom of case.

The longer lead on the LED is the positive lead and must be placed through the bottom of the bulb case to contact the positive battery post.

Bend the short (negative) lead as shown. If there is a slot at the side of case, point the lead at the slot.

Heat the solder ball at the bottom of the case and slide the long lead through it when it melts.

Place the negative lead in the slot or against the side of the case and solder in place. After both leads are soldered, cut off the excess and remove any solder from the side of the case. Make sure there is still a good solder-ball at the bottom of the case.

Fill the case with 5 minute epoxy to support the LED bulb and leads.


Justme


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