Introduction: Useful Components in the Base of a Burned Out CFL Light Bulb.
A burned out CFL home light bulb provides a nice little easter egg for the electronics hobbyist.
Just pry off the base with a jacknife inserted in the seam, and it comes apart easily.
The circular PC board contains a lot of usefull parts, apart from it being a ~700v switching power
supply, if it still works. If the condition that caused the CFL to burn out is the CFL itself, you have a
complete set of components, otherwise, one (or more) of these components will be cooked. All
components are easily de-soldered from the pc board.
Check it out:
I have broken down the components and identified them. I also detailed the 2 power transistors,
by providing info from the data sheet.
CFL: integrated power supply
2- DK45 Silicon NPN power switch transistor
PNP/NPN PCM (W) ICM (A) BVCEO (V) BVCBO (V) BVEBO (V) IC (A)
VCE (V) min Max IC (A) IB (A) max (V) IC (A) VCE (V) f (MHZ) min (MHZ)
DIE SIZE (mm2) PACKAGE
NPN 68 4 220 350 9 0.5 10 10 60
2.0 0.5 1.0 0.5 10 1 4 2.34×2.34 TO-220
1- 1 1/4" dia. pc board.
6- 1N4005 diodes
1-22uf 200v Electrolytic capacitor
1-10k resistor 5%
1-22k resistor 10%
2-1k resistors, 10%
1- 3N 471k 1kv ceramic capacitor 700pf
1- CBB18 poly film capacitor 1kv .47uf
3- CJB 104k poly film capacitor 400v ?uf
1- mini transformer
2- mini choke coils
2-small 2"" leads of high temp thermal insulated wire.
Make sure that you properly recycle the CFL portion of the lamp. It is not very environmental friendly
since it contains Mercury.
Hope you get some usefull parts for your next project!