## Tuesday, February 24, 2015

### How to make LED board (method 1)

LEDs because of the diversity of colors, strong lighting and consume little power used in many areas, can use for write letters and draw shapes.
In following video you can see how it can.
The LEDs must connect together in parallel, means all positive connect together and all negative connect together so you can run that with 2 to 3.5v (according to led types).
you have to using a resistor through positive line to protect your LEDs and increase its life period.(see the note)

you can use second method for big LED boards.

Parts list:
battery
Text or shape printed on a paper
Solder flux
LED(number of LEDs depend on your text or shape )
Resistor (see the note)

Note:
Protection resistor used when supply power is more than standard LEDs voltage, its value depends on number of LEDs, LEDs type(color) and voltage of battery or power supply.
You have to using ohm's law for calculation the value of necessary resistor.
in first run your LED board by 2 to 3v battery and use a DC Ammeter to measure the current consumption,

then put that current value in the ohm's law equation with voltage that you want(for example 12v if you want to run your LED board by car battery)
Now you can find the value of resistor as follows :

R= (Vs-Vf) / If

Where:
Vs is voltage(volt) of battery or power supply,
Vf is voltage needed to running the LEDs
If is the current consumption of LED board(Amp)
R is protection resistor that you need(ohm)

R= (12-2) / 0.164
R= 60.97 ohm

Power of the resistor:

P= (Vs-Vf) * If

P= (12-2.5) * 0.164
P= 1.5 W

So i have to use 62 ohm 1.5W resistor for 12v battery.

This is only an example, your LED board maybe need to other resistor value.

You can connect each 5 LEDs (or 4 LEDs for white or blue color) together in SERIES if you want to running the LEDs by 12v, in this case you don't need to resistor to protection because the LEDs voltage will be suitable to battery voltage as you can see in following figure.