Replacing Old Flashlight Bulb With LED




About: Just an ordinary person who loves #thinking and #tinkering

It was my boy finding this classic flashlight and asking me to make it works. Replacing the batteries with new ones didn't make it work. Then I took it apart, saw that the bulb's flashing wire had broken. Searching all around (my house) I couldn't find a replacement bulb. Seeing two AA batteries (3V) made me think of replacing it with a white LED. Why not? I have plenty of them around ^_^

Step 1: Parts and Tools

Parts :

  • A classic 2 x AA battery flashlight.
  • A white LED.
  • 2 cm of small cable [18-22 AWG will do]. We need its jacket only.

Tools :

  • Wire cutter.
  • Solder.
  • A small head screwdriver.
  • Hot glue [optional].
  • File [optional].

Step 2: Get the Bulb Base

Take off the bulb from its base. It is small and fragile. You just need to move it left-right-left-right until it get loosen, then pull it out. Clean the whole base using a small screwdriver.

Step 3: Prepare the LED

Bend the cathode (-) of your LED forming 90 degrees from the anode (+) of the LED. Well, for instant, the larger piece inside the LED is cathode and the smaller piece inside is anode. So far I keep remembering LED anode-cathode in this way, because I was once wrong when using longer-shorter pins due to factory's fault. For more confirm, please connect the led directly to 3 Volts battery, it won't light up if you put it the wrong way. Then bend the pin connected to the negative (-) of battery just like the photo above.

Get a small piece of wire, we need its jacket only, any wire whose jacket fit the LED pin. Pull out the wire strands, then put the LED anode (+) pin in it. This is to avoid shorting to the negative base.

Now bend the cathode (-) pin down to the former bulb negative solder pad then smoke it... I mean solder it there :)

We are almost done :)

Step 4: Finishing

I use clear tape to seal the border of the anode (+) pin to avoid short. Actually I intended to fill it up with hot glue to make the LED steady on its new container but at that time I couldn't find one, while the deadline given by my son was expiring that day :D

So.. I lighted it up anyway.

If you have a file handy, clean up the bulb negative contact which will be touched by the sliding switch connecting it to the negative of battery.

A happy Son, a happy Father, and an old stock brand new Flashlight ^_^

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    18 Discussions


    4 years ago

    been needing to do this to my old MAG light' the bulbs are just to dull, but never could figure out if I needed a resistor or not for it thank you very much great ible

    5 replies

    Reply 4 years ago on Introduction

    You can use it without a resistor but you should use a resistor because without one the LED won't last long.


    Reply 10 months ago

    Yes, I agree. Without the resistor, the LED is still drawing as much current as possible and will drain the battery instead.


    Reply 10 months ago

    Thank you for enlightening me. Then I guess I need an 1-ohm resistor in this case to keep its brightness? :D


    Reply 4 years ago

    Red, yellow or green led has 1.8V forward voltage , yes you need 48 ohm resistor. But for white led, it has 3.3V forward voltage. I am using 2 AA batteries (2 x 1.5 = 3V) so I don't need a resistor. If your battery voltage is more than 3.3V then you need a resistor. Here is a good explanation about led and resistor needed :)


    Reply 4 years ago

    Thank you. Just do my best for iBle community ^_^


    Reply 4 years ago

    Thank you. It is my boy with his deadline make this works :D