5V vs 12V
Usually one of the first questions is which one should I buy?
In general 12V pixels are more popular than 5V.
In a longer answer we need to understand how a pixel works.
Pixels come in 2 main types of voltage in our hobby. The 5V and 12V version. It is always a debate on which one is better. To be honest they both have their advantages.
All pixels actually run on 5 volt DC power. The way a 12 volt pixel works is by reducing the 12 volt power down to 5 volts by adding either resistors or regulators to the chipboard. The 5 volt power is then used to power the pixel LEDs. The 12 volt from the wire then continues down the strand as 12V power to the next pixel.
Here is an example of a 12V resistor pixel.
Here is a 12V Regulated pixel.
This is why you'll see 5 volt pixel looks like it is missing items on the chipboard. It is only because if you are running 5 volt power already it doesn't need to be reduced to power the pixel.
This is a picture of a 5v pixel board. Notice it doesn't have as many components of the previously pictured 12v pixels.
Here are some pros and cons of both.
5 Volt Pixels:
You must power inject more often
Not as readily available
12 volt Pixels
Can run more pixels with less power injection
More Readily Available