Led Bulb


Introduction: Led Bulb

About: I am a DIY person. I am a professional in software, micro controllers and and some circuitry.

This is a led bulb that i made from a broken CFL bulb and some Leds that i had laying around.

I already made 2 led bulbs. The one on the left is 1 watt and the one on the right is the 3 watt which im showing you now.

These bulbs are for 120v mains.


Do not touch the output when open or closed circuit, it is still referenced to MAINS!


Step 1: Parts Needed.

1) 1-dead or new CFL bulb

2)4-470k ohm resistors

3) 1-120ohm resistor(may be in the CFL bulb)

4) one 200-400nf capacitor(will be in the CFL bulb)

5) 2-330nf capacitor (i used it because, the current output wasnt enough)

6) Any polarized capacitor from the CFL light bulb for DC smoothing ( You should use a 100-200uf capacitor)

7) 4-diodes (from the CFL bulb)

8) perf board

9) copper PCB board

10)5050 led chips( i had them laying around, but u can you use any leds but you have to change the total capacitance of the group of capacitors to limit more or less current) use this website to calculate the resistance from the capacitor value--------http://www.66pacific.com/calculators/xc_calc.asp

And use this website to calculate the the current that it will limit, use the middle calculator----http://www.digikey.ca/en/resources/conversion-calc...\

(Also if you want to use these bulbs for 240v, use the calcuators above to find the appropriate non-polarized capacitors needed)

Step 2: Taking Apart the CFL Bulb

First i used a hacksaw to saw around the plastic casing( the top seam of the plastic base), opening up and out the important electronic components. (be very careful when sawing it apart, trying not to crack the cfl glass bulb which has mercury in it)

I soldered out 4 diodes, the polarized capacitors, and non polarized capacitors.

Step 3: Creating the Led Driver Board

Start cutting out a larger piece of perf board that fits inside of the CFL housing and start creating and soldering in resistors, capacitors, diodes, in the circuit above which look like this.

The diodes should be wired in the orientation above.

The non polarized capacitors should be all wired in parallel to get the correct total capacitance of 1uF, but capacitance can be larger for larger Leds.

Step 4: Making the Led Board

I used 5050 led chips, so they are surface mounted so i needed a PCB board, but i couldn't etch the copper board with any chemicals, since i didn't have any chemicals, nor the tools to make the board.

So i etched the board using the DIY way, by creating the board by drawing the board out with marker (my Leds are all wired in series), then covering the parts i wanted in aluminum tape. Then creating an etching solution of 1 part vinegar and 1 part hydrogen peroxide. I let the board sit in the solution for 12 hours, overnight.

After 12 hours it looked like this and i cleaned off the aluminum pieces and the etching solution and i was left with a cup of blue liquid and cleanly etched circuit board.

(you can wire as many Leds in series as long that the total voltage of the Leds isn't more than the supplied mains voltage of 170v (after rectification, 120v before).

Step 5: Nearly Done!

After the driver board was finished, i soldered it to the CFL edison screw base and sealed the board in the base with hot glue with 2 wire pertruding from the case.

Then after the tiring work soldering in the 5050 chips, i was finalling able to put in all together and testing it out.

(near finished soldering of the LEDs above)

Step 6: Finished!

Since everything worked, i glued the led board on the the lamp base, with a piece of cardboard separating the CFL base from the Led board.

And now it puts out 3 watts of light which is enough to light my kitchen table brightly.

Don't touch the face of the led board when the light is on, or you can get a used,clean and translucent plastic container to cover the led board and diffuse the light, preventing electrocution.




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    12 Discussions

    is the diode you used is 1N4007

    for 16 led SMD5730 (2,8V~3,6V) 150mA each 0,5W >>>>>> FOR 220V use C1= 1,5uF, remove R1, R2 drain resistor= 470K, remove R3, C4= 47uF 100V or 50V, R4 ( drain) 470K

    Original circuit China LED lamp.

    IMPORTANT! Do not remove the LED when energized, if it occurs, the capacitor C4 may burst (Poowww)

    you would to change the total capacitance of the capacitor on the mains from 1uf to 1.2-1.4uf. And you would use the 400v polarized capacitor in the cfl bulb to smooth out the dc side. Everything else in the circuit would be the same.


    2 years ago

    Power LED should be driven by constant current source, otherwise it can be easily damaged.

    2 replies

    yes they should be, but my circuit is actually under driving my leds by 10-20 milliamps with the 1uF capacitor to make it safer.

    for 16 led SMD5730 (2,8V~3,6V) 150mA each 0,5W >>>>>> FOR 117V use C1= 3,4uF, remove R1, R2 drain resistor= 470K, remove R3, C4= 47uF 100V or 50V, R4 ( drain) 470K

    Original circuit China LED lamp.

    Great instructable. Just wondering... Are these custom bulbs more durable and even when they break, could they be repaired and reused?

    1 reply

    yes they are more durable, i dropped the bulbs multiple of times when trying to screw them in. You can repair and reuse them, if you pry the hot glue off the led board and the cardboard underneath, the parts can be easily accessible to repair or to reuse the parts.