This instructable covers the transformation of a lamp room that had previously been supplied to a lamp of 20w halogen, with consumption of 1w led light with a current savings and optimal lighting.
Since the bulb of 20w 12v was powered, I preferred to replace the one that had transformer with a voltage which approached more than typical diode which is about 3.5 v; I had a trsformatore surplus from 4 .5V that did just in case my putting a resistor in series of limitation of 18 ohm (in my case I used 4 of 75 Ohm resistors in parallel), I got a measured current of about 140 but that is a value of half of the nominal current for this diode (300mA) thus obtaining diode protection in case of overvoltage of voltage.
Step 1: The Ingredients
In the photo are the main ingredients of realization:
A bedside lamp
1 w led
a transformer voltage 4, 5v, 500ma; the current is about 1/3 of maximum value.
In the photo appear then the old CDs which originally wanted to use to create a spotlight, then I abandoned that idea and I are oriented to the use of a reflector "retrieved" by an old portable stack, as seen from the picture below.
After carefully "gutted" lamp by removing almost all components and leaving virtually only the on/off switch and the structure, I have begun to accommodate the new components starting with the transformer that I lodged as seen in Figure trying to place to avoid touching the switch that protruding internally is quite.
Step 3: Led and Reflector
Then I fixed it with hot glue the diode reflector; a note about Spotlight:
to obtain a scattering of light as much as possible, I washed with silver spray the surface of the speaker because otherwise it made some weird reflections.
Step 4: Links
I connected the various components together using wires connecting the stem which act as conductors to do get the diode voltage. As I said previously is curbing resistance comprised four 75-ohm resistors 1/4 w in parallel which are covered by a current total of 140 but for a total of 18 ohm resistance.
The reflector was fixed to the lamp with three abundant liquid glue drops: after "fired" the glue I nestled gently diffuser keeping it in the correct position until curing.
Now I was that close the shell containing the transformer and secure it with screws. Here is the result.
Step 6: Finally
And finally here's a gallery of photos of the lamp lit to give an idea of the light which IMHO is notable.
In the coming days I will measure comparing the use of this lamp with a traditional lamp mounting a 20 w halogen bulb.
We consider that the led working about 1/2 power, because I preferred to maintain the current low values to avoid, in the case of excessive current protector, a resulting deterioration of the diode.Even with this current optimum brightness gives a diode that permits a comfortable night and shadow areas.
Thank you for your attention, I hope I was clear in my explanation, if you have any questions I'll be happy to answer on these pages, goodbye!