Power Supplies

Power supplies convert mains electricity or battery energy into the regulated DC voltage that LED circuits require.

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Power supplies convert mains electricity or battery energy into the regulated DC voltage that LED circuits require. Every LED project needs a power source, and choosing the right supply determines whether your LEDs run at full brightness, at the correct color temperature, and without the overheating, flickering, or premature failure that come from a mismatched power source. We organize our power supply inventory into two main categories: AC-to-DC power supplies that plug into a wall outlet and deliver regulated DC output, and battery power supplies that provide portable, cordless LED power from coin cells, AA/AAA cells, and rechargeable packs.

AC-to-DC power supplies are the standard choice for any LED installation that has access to a wall outlet. Our selection covers the two most common LED supply voltages: 12V for LED strips, pre-wired LEDs, and automotive-style circuits, and 5V for Arduino, ESP32, and other microcontroller-based LED projects. For 6V and 9V projects, use our 4xAA (6V) and 9V battery holders. Within the 12V range, we offer two form factors — compact wall adapters rated 1A, 2A, 3A, and 5A (12W to 60W) for small and mid-size LED installations, and high-output desktop supplies rated 3A (35W), 5A (60W), 8.5A (100W), 16.5A (200W), and 25A (320W) for large LED strip runs and multi-zone installations. All of our AC-to-DC supplies output regulated, filtered DC — the voltage stays constant under load, and the output is clean enough for sensitive LED circuits without additional filtering.

How to choose the right power supply for your LED project: Start with voltage — the supply voltage must match what your LEDs require. 12V LED strips need a 12V supply. 12V pre-wired LEDs work on 5V too, a little dimmer (a 12V supply gives full brightness), and 12V built-in resistor LEDs run on 5–15V (round tops) or 7–15V (cubes). Bare component LEDs with external resistors work on 5V, 9V, or 12V — the resistor value accounts for the supply voltage. Next, calculate the total current draw of your LED installation. Each product page lists the current or power per unit (mA per LED; for our LED strips, watts per 5-meter reel and mA per 5cm section, which works out to about 0.4A per meter for 3528 strip and 1.2A per meter for 5050 strip), and you multiply by the number of units. Add a 20% safety margin to the total — this prevents the supply from running at maximum rated output, which generates excess heat and shortens its lifespan. If the total current exceeds what our largest wall adapter can provide (5A, 60W), step up to a high-output desktop supply.

Wall adapters vs. desktop supplies: Our 1A and 2A wall adapters plug directly into the outlet, and the 3A and 5A models are compact power bricks with a detachable IEC power cord; all four have a 5.5mm x 2.1mm barrel plug output. They are compact, inexpensive, and ideal for small projects: a few meters of LED strip, a handful of pre-wired LEDs, an Arduino with a sensor and display. Our high-output desktop supplies are larger enclosed metal-case units with screw terminals instead of cords: you wire an AC power cord to the input terminals (L, N and ground) and connect your LED wiring to the DC output terminals. They come in 3A (35W), 5A (60W), 8.5A (100W), 16.5A (200W), and 25A (320W) ratings, cool through vented metal cases (the 16.5A and 25A models also have built-in cooling fans) for sustained high-load operation, and support the long wire runs typical of architectural, signage, and commercial LED installations. For mid-range projects, our 3A (36W) and 5A (60W) wall adapters fill the gap: the 3A adapter runs a full 5-meter reel of 3528 strip (24W), and the 5A adapter runs up to 3 meters of 5050 strip (43.2W).

Voltage regulation matters for LED longevity. A regulated power supply maintains a constant output voltage regardless of how much current the load draws (up to the supply’s rated maximum). Unregulated supplies allow the voltage to rise under light loads and sag under heavy loads — this voltage variation changes LED brightness, shifts color temperature, and can exceed the LED’s maximum forward voltage rating, causing premature failure. All of our AC-to-DC supplies are regulated. If you are repurposing a surplus transformer or an old wall adapter, check whether it says “regulated” on the label. If it does not, measure the no-load and full-load output voltage with a multimeter before connecting LEDs.

Battery power supplies provide portable, cordless LED lighting for projects that cannot connect to a wall outlet. Our battery holder selection includes single and multi-cell holders for AA, AAA, and coin cell (CR2032) batteries, with options for leads, snap connectors, and built-in switches. Battery power is standard for model railroad rolling stock (LED-lit passenger cars), wearable LED costumes and accessories, holiday ornaments, portable prop lighting, science fair projects, and any LED application that needs to move freely. Battery voltage depends on the cell chemistry and count — a 2xAA holder provides 3V (matching a single blue/white LED’s forward voltage), a 4xAA holder provides 6V, and a 3xAA holder provides 4.5V for a wide range of configurations. Coin cell holders power low-current applications like LED throwies, miniature model lighting, and wearable LED jewelry.

For projects running on AC power from a landscape transformer or DCC model railroad track bus, see our bridge rectifier category to convert AC to DC before feeding LEDs that need DC, such as flashing, flickering, and color-changing LEDs (they also need a smoothing capacitor after the rectifier); our 12V solid-on pre-wired LEDs work directly on DCC (up to 15V track voltage) or low-voltage AC. For the steadiest light, run them on DC or add a bridge rectifier. For help selecting the right resistor to pair with your power supply voltage and LED, use our LED Resistor Calculator. Browse our component LEDs, pre-wired LEDs, LED strips, and wire and connectors to pair with the right power supply for your project.

Frequently Asked Questions

Match the supply voltage to your LED product. 12V LED strips require a 12V supply. 12V pre-wired LEDs work on 5V too, a little dimmer (a 12V supply gives full brightness), and 12V built-in resistor LEDs run on 5–15V (round tops) or 7–15V (cubes). Bare component LEDs with a current-limiting resistor work on 5V, 9V, or 12V — the resistor value is calculated based on the supply voltage. Arduino and ESP32 projects typically use 5V. The product page for each LED lists the recommended supply voltage.
Add up the current draw of every LED or LED strip in your installation. Each product page lists the current or power per unit — typically 20mA per standard component LED; our LED strip pages list watts per 5-meter reel and mA per 5cm section (about 0.4A per meter for 3528 strip and 1.2A per meter for 5050 strip). Multiply by the number of units and add a 20% safety margin. For example, 50 LEDs at 20mA each = 1A total; with 20% margin, choose a supply rated for at least 1.2A. A 5-meter reel of 5050 strip drawing 1.2A per meter = 6A (72W) total; with margin, choose at least 7.2A, which means our 8.5A (100W) supply.
A wall adapter plugs into the outlet (our 1A and 2A models directly, the 3A and 5A models through a detachable IEC power cord) and delivers low to moderate current (our 12V wall adapters are rated 1A to 5A). It is compact and ideal for small projects: a short LED strip run, a few pre-wired LEDs, an Arduino setup. A desktop (high-output) power supply is a larger enclosed metal-case unit with screw terminals instead of cords (you wire the AC power cord to its input terminals), delivering higher current (up to 25A, or 320W, in our 12V range) for large LED installations — long strip runs, multi-zone lighting, commercial signage. The 16.5A (200W) and 25A (320W) models have built-in cooling fans, and the screw-terminal outputs make high-current connections easy.
A USB phone charger outputs 5V DC, so it can power LEDs that run on 5V — such as the 6V pre-wired LEDs (which work great on 5V), bare LEDs with a resistor calculated for 5V, or Arduino-based LED projects. It cannot power 12V LED strips — those require a 12V supply. 12V pre-wired LEDs work on 5V too, a little dimmer (a 12V supply gives full brightness). Check the charger’s current rating (printed on the label) to make sure it can supply enough current for your LED load.
Strongly recommended. A regulated supply maintains a constant output voltage regardless of load, ensuring consistent LED brightness and color temperature. An unregulated supply lets voltage rise under light loads (potentially exceeding the LED’s maximum rating and shortening its lifespan) and sag under heavy loads (causing dim, inconsistent brightness). All of our AC-to-DC power supplies are regulated. If reusing an old adapter, check the label for the word “regulated” and verify the output voltage with a multimeter before connecting LEDs.
Yes. Battery holders are ideal for portable, cordless LED projects — model railroad rolling stock, wearable costumes, holiday ornaments, and props. A 2xAA holder outputs 3V (matches blue/white LEDs directly), a 3xAA outputs 4.5V, and a 4xAA outputs 6V. A CR2032 coin cell (3V, ~220mAh) powers low-current LEDs for hours in throwies, miniatures, and jewelry. Calculate battery life by dividing the battery capacity (in mAh) by the LED current (in mA). A single 20mA LED on a 2xAA pack (2500mAh) runs for about 125 hours.