The Complete Guide to Series and Parallel Circuits for LED Strip Lighting Project

Table of Contents

Series or parallel

The core of LED strip connection lies in its internal circuit logic. Series and parallel connections are two of the most basic circuit connection methods. Proper method selection guarantees even and bright lighting, whereas improper selection creates insufficient brightness or safety hazards.

This article will explain the differences between these two circuits in the simplest way, and tell you their advantages and disadvantages. If you understand the difference between circuits in series and parallel, you can avoid the hidden dangers of uneven voltage or single-point failures quickly, and this ensures more stable operation of the LED strip.

Series Circuit

Basic Circuit Structure

1. Internal Series Structure

Let us take Group 1 as an example. It consists of 6 LED beads connected in series.

If any one of the LED beads fails, the entire series circuit breaks, and all 6 LED beads in Group 1 will turn off.

2. Parallel Connection Between Groups

Groups 1, 2, 3, and 4 are connected in parallel:

When Group 1 turns off due to the failure of its internal LED beads, Groups 2, 3, and 4 are completely unaffected and continue to emit light normally.

Similarly, Groups 5-8 and 9-12 have the same circuit structure.

3. The three LED strips in Groups A, B, and C are connected in series.

Parallel circuit

1. Similar to the basic series circuit structure described above, within each group (e.g., the 6 LEDs in group 1), the LEDs are connected in series. And within the same LED strip, groups 1, 2, 3, and 4 are connected in parallel. Similarly, groups 5-8 and groups 9-12 are also in basic parallel circuit.

2. The three LED strips A, B, and C in the diagram above are connected in parallel. As shown, groups A, B, and C are connected side-by-side at both ends of the power supply.

For more information about the connection, you can click on: How to Wire and Code WS2818 LED Strip on ESP8266    How to Wire and Code SK6812 RGBW LED Strips on Raspberry Pi.

Practical Application Forms of LED Strips

In actual purchased LED strips, you will rarely see pure series or pure parallel circuits. Instead, a combination of series and parallel is used, with the focus varying based on voltage.

The cutting unit of an LED strip directly determines its internal series and parallel circuit structure, which in turn affects the voltage selection (12V vs 24V) and the final performance.
 
The operating voltage of a single LED bead (taking 2835/5050 as an example) is typically 3V.

12V LED Strip: 3 LEDs + 1 resistor = 1 unit

3 LEDs in series: 3 × 3.2 V = 9.6 V

Residual Voltage: 12 V − 9.6 V = 2.4 V

This 2.4V is handled by the current-limiting resistor and dissipated as heat.

Parallel Connection: The entire LED strip is composed of hundreds or thousands of “3-series units” connected in parallel.

12v led strip

24V LED Strip: 6 LEDs + 2 resistors = 1 unit

6 LEDs in series: 6 × 3.2 V = 19.2 V

Residual voltage: 24 V − 19.2 V = 4.8 V

This is borne by the current-limiting resistor.

Cutting unit: 6 LEDs per cut.

Parallel connection: The entire LED strip is composed of hundreds or thousands of “6-series units” connected in parallel.

24v LED strip

Whether it’s 12V or 24V, the overall structure of the LED strip is a parallel connection. The so-called “series wiring” refers to connecting multiple LED strip segments end to end during external installation, while the internal microstructure is always “series first, then parallel“.

Pros and Cons of Series and Parallel 

Pros and Cons of External Series

Advantages Disadvantages
1. Simple WiringInstalls quickly and saves a lot of cable. 1. Voltage DropIf you connect more strips in a row, the total resistance increases greatly, resulting in uneven brightness.
2. Smooth Signal TransmissionWorks best with programmable strips. The data moves in a simple chain, skipping complex distributors. 2. Risk of OverheatingIf wires are too thin or too many strips are connected, high current can cause connections to overheat.
3. Clean InstallationReduces visible power cables, keeping the setup neat and tidy. 3. Overpressure RiskUsing high-voltage power for low-voltage strips to overcome voltage drop can damage rear sections immediately.
LED STRIP IN SERIES 1
LED strip in series

Pros and Cons of External Parallel 

Pros Cons
Uniform BrightnessEach LED strip draws its full voltage directly from the power supply to achieve consistent lighting. Complex WiringThis setup requires multiple cables and distribution boxes, increasing labor and concealment difficulty.
Flexible ControlYou can easily add separate switches or controllers to each section, allowing independent control of different lighting areas. Higher Material CostThicker main cables are required to carry the total current, increasing branch wiring volume.
Easy to ExpandAdd new sections anytime as long as the power supply and main cable can handle the extra load. Each new section works independently. Space IssuesJunction boxes and split points require sufficient room, which is often limited in narrow channels.
led Strip in parallel
LED strip in parallel

The 48V LED strips reduces the current of the same power by 75%, which almost eliminate voltage drop loss, and establish the series scheme as the preferred choice for long-distance lighting. Here are three major advantages: fast installation, simple wiring, and low cost. 

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