Here I am for presenting my first instructable...
I am a boy from Tuscany, so... Sorry for my english!
Step 1: Materials
Main items that we need:
- a connection of an old bulb lamp
- a transformer
- 2 diodes
- 2 capacitors
- 2 5x20 fuses (2 A)
- 1 LM7824
- 1 thin aluminium sheet
Step 2: Electric Circuit
These simple circuit is composed from three parts.
The first part is the transformer. I have a 230/12 V transformer but I have a 24 V led strip, so we need the second part of the circuit.
The second section is a voltage multiplier, that is very similar to a rectifier bridge, but composed by 2 diodes and 2 capacitors, instead of 4 diodes. With this bridge we raise the voltage about 30 - 35 Vcc with a ripple.
The third section is the integrated circuit LM7824, that helps us to have 24 Vcc, not still pure, but perfect to give power to a led strip. To have a flawless 24 Vcc we need 2 or 3 capacitor before and after the LM7824 to filter and level the voltage but I haven't enough space.
Step 3: The Led Strip
The strip absorbs 0,046 A each 10 cm, we use 200 cm of strip, so the current will be 0,92 A. The maximun current that gives the LM7824 is 1 A, I know that this is an extreme situation, but this is only a prototype, an also we put an heatsink on it.
Step 4: The First Part
Let's make the first section, solderind the bulb connection, the 2 A fuse an the primary coil of the transformer. The transftormer enters perfectly in the plastic "bowl" of the bulb lamp, than we can try the circuit voltage.
Step 5: The Second and the Third Parts
We need a round shaped board to mount the circuit on it, put the heat-sink with a little bit of silicon conductive paste on the LM7824, make a nock with the dremel for the wires passage.
Finally we can try the voltage and the strip worrking.
Step 6: The Strip Holder
Working on the aluminium sheet we must shape it into a cylinder, that enters in the place where there was the glass ball. I hope that the pictures explain better than me the process. The width of the sheet is determined by the length of the strip.
Step 7: The Last Step...
Mounting the strip on the cylinder with some cable tie and connect it to the circuit.
Finally arrives the test... OK!
In the last photo, with the horizontal bands that you caught only with the camera, you can see that the output voltage is not perfect but a bit fluctuating, as previously described...
Thanks for reading my instructable! Sorry for my imperfect english!