LED Wiring; Series vs Parallel vs Series-Parallel


How a circuit is wired will determine the voltage and current needed to properly operate the circuit. Below you will see two circuits using five LEDs 160-1445-1-ND. This is a 2V 20mA LED. As you can see there is a drastic difference in the voltage and current needed to operate each of these circuits.

Parallel components have the same voltage across them but fluctuating currents.
Series components have the same current through them but fluctuating voltages.
Generally speaking, most LED lighting uses a series-parallel combination.
Ideally, for reliability and lighting consistency, it would be best to have one strip of LEDs all wired in series to a constant current driver. This is usually impossible for long strips due to the very high voltage the LEDs would require, but also if one of the LEDs were to burn out then the entire strip would not light, where with combinational series-parallel wiring, only one part of the strip would not light which will still leave some lighting.

Keep in mind when an LED(s) burns out, gets damaged, or is cut from a strip in a combinational constant current circuit that the remaining LEDs may be damaged, as the fixed current may be too high for the remaining LEDs. This is yet another reason constant voltage drivers are easier to work with and usually preferred for series-parallel combinational circuits.

Choosing the correct LED and LED Driver