Here at Digi-Key we sell many different types of LEDs. When looking at LED linear strips we typically have two types different types.
Hard or board strips
These strips come in fixed lengths are not flexible and will normally have solder pads on the end to solder your wires to.
Let’s look at part 1568-1136-ND
For example, this strip has multiple parallel branches of 3 LEDs wired in series. Series-parallel combinations allow the LED strip to be cut at certain sections. These can use a constant voltage LED driver of the required voltage and equal or greater current, or a constant current driver of the exact current required by the strip once the strip length has been determined and within the voltage output swing.
We also have some fixed strips that are prewired such as 365-1494-ND
Flexible lights strips like fixed light strips also have solderable pads on the end. For a simple LED this may be just a power and ground.
You will also find strips of LED listed under addressable or specialty LEDs. While similar in shape they will generally have 3 or more contacts.
The additional contacts being used for communication. If you look at part 1528-1082-ND is an example of addressable LED strip, these are neat as they have a constant current driver chip built into each LED so it only requires a constant voltage driver.
Each LED is individually addressable making the lighting possibilities next to endless. 1528-1582-ND is yet another addressable example but this also has white lighting along with RGB lighting.
When looking at any flexible LED strip it is important to verify the length of the strip by description and not only the photo. Some shorter pieces may have the same manufacturer part number as the full reel but since we cut shorter pieces from full reels such as 1’’ or 2" strips it is best to verify before ordering.