LED Driver (5 LEDs)

Picture of LED Driver (5 LEDs)

This is a simple LED driver/power supply for 5 LEDs. Parts:
It uses the LM7812 positive voltage regulator,
2x 0.1uF Capacitors
1000uF/16V Capacitor
RBV - 406 rectifier
5 LEDs (I used transparent green)
A 12V transformer ~500mA
For Typical Forward Voltage use 78 - 100 ohms resistor for Max Forward Voltage use 15-30 ohms resistor
Spark Design PCB:
Laser Printer
Glossy Paper
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Step 1: Build it

Picture of Build it
1) Print the schematic on glossy paper and use toner transfer method. (Print only Board Outline and Bottom Copper Side)
2) Etch
3) Remove toner
4) Acquire components and solder them as showed in schematic
5) Solder power cord to primary wire windings and connect the transformer
6) Measure for shorts and insulate primary wires, check the polarity of Electrolytic capacitor and LEDs and check the rectifier and 7812

Step 2: Use it

Use it for keyboard illumination or give a glow to a drink and have fun!
Find a box to put it in if you want and/or add a switch.
Sorry for grammar mistakes or something like that :D.
tutdude989 months ago
7812 needs more than 14V input so output with 12v input will be about 10V
Mock5 (author)  tutdude989 months ago
For a full-wave rectifier, the DC output will be 1.414 times the AC output. So the output of rectifier will be about 16V.
tutdude98 Mock59 months ago
thats peak value
With some load it would be 12V - 1.3V (voltage drop from 2 diodes) = 10.7V and if you put that on 7812 youl get approx. 9V
Ploopy9 months ago
Where did you get the transformer?
Mock5 (author)  Ploopy9 months ago
Here in romania I get it from here :
It is a 12V 800mA transformer
Ploopy9 months ago
Ploopy9 months ago
Ploopy9 months ago
Could you post a schematic picture, I'm confused

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