Series Circuit
Often referred to as ‘daisy-chained’ or ‘looped’ the current in a series circuit follows one path from start-to-finish with the Anode (positive) of the second LED connected to the Cathode (negative) of the first. The image to the right shows an example: To wire a series circuit like the one shown, the positive output from the driver connects to the positive of the first LED and from that LED a connection is made from the negative to the positive of the second LED and so on, until the last LED in the circuit. Finally, the last LED connection goes from the negative of the LED to the negative output of the constant current driver, creating a continuous loop or daisy chain.
Note:
Same current flows through each LED
The total voltage of the circuit is the sum of the voltages across each LED
If one LED fails, the entire circuit won’t work
Series circuits are easier to wire and troubleshoot
Varying voltages across each LED is okay
Parallel Circuit
Where a series circuit receives the same current to each LED, a parallel circuit receives the same voltage to each LED and the total current to each LED is the total current output of the driver divided by the number of parallel LEDs.
In a parallel circuit all the positive connections are tied together and back to the positive output of the LED driver and all the negative connections are tied together and back to the negative output of the driver.
Note:
The voltage across each LED is the same
The total current is the sum of currents through each LED
The total output current is shared through each parallel string
Exact voltages are required in each parallel string to help avoid current hogging