Wefomey Universal Power Supply 3V~24V 3A 72W Adjustable Variable 3V 5V 9V 12V 18V 20V 24V AC/DC Adapter Charger, 100V-240V AC to DC Converter with 14 Tips, Polarity Converter and 4-Way Power Splitter Cable

Overview

I keep a universal adjustable power supply on my bench for the odd jobs that never quite fit a dedicated brick. The Wefomey universal adapter has been in that slot for a few weeks now, filling in as a quick test supply, a stand‑in for lost wall warts, and a handy way to power multiple low‑draw devices from one outlet. It’s a 3–24V, 3A (72W) AC‑to‑DC supply with a backlit LCD, a rotary adjustment knob, and a generous kit of connectors, including a reverse polarity coupler, an alligator lead, and a 1‑to‑4 splitter.

This isn’t a lab supply, and it doesn’t pretend to be. But as a practical, compact, and reasonably priced tool for hobby benches and around-the-house fixes, it gets a lot right—so long as you understand its limits.

What’s in the box

Wefomey includes more than most in this category:

• 3–24V adjustable supply with LCD readout
• 14 DC tips: common barrel sizes, Micro‑USB, USB‑C, and a screw terminal block
• A reverse polarity adapter for center‑negative gear
• An alligator clip test lead
• A 4‑way splitter (1 female to 4 male) for powering multiple devices
• About 6 feet of mains and output cable combined

It covers the most common barrel sizes, from 5.5x2.1mm (the default) and 5.5x2.5mm down to the smaller 3.5x1.35mm and 2.5x0.7mm types. The screw terminal tip is especially useful for oddball connectors or bare‑lead prototypes.

Design and interface

The supply is compact and silent in operation—no coil whine in my unit. The LCD is simple but genuinely useful; it shows the set output voltage, reducing guesswork. The adjustment is a free‑spinning potentiometer, not stepped presets, so you can hit odd voltages between the usual 3/5/9/12/15/18/24V points.

A couple of caveats with the interface:

• There’s no lock or detent on the knob. If you bump it, the voltage changes. For anything sensitive, I set the voltage, verify with a meter under load, and add a small piece of tape over the knob as a makeshift lock.
• At low voltages, the adjustment is touchier. Small movements can shift the output by tenths of a volt. It’s workable; just go slow.

Performance and accuracy

For a small switch‑mode supply, it’s impressively usable. A few notes from my testing:

• The LCD on my unit reads slightly high—about 0.1V above actual output across most of the range. That’s consistent within a few hundredths and easy to compensate for.
• The output lead uses thin wire typical of wall adapters. Expect voltage drop at higher currents. At 3A, I measured roughly 0.5–0.6V drop across the stock lead. For a 5V single‑board computer drawing 2A, that can matter. The simple fix is to set the output a bit higher to account for drop under load.
• Ripple and noise are within what I’d expect for a compact adapter; it’s fine for LEDs, routers, cameras, and hobby electronics. If you’re powering precision analog circuits, you’ll want a bench supply anyway.
• Thermal behavior is acceptable. The case gets warm near the top of the range, but I didn’t encounter thermal cutoffs running sustained loads around 2A. As a rule, I try to stay under about 80% of the 72W rating for continuous duty.

The protection circuitry—over‑voltage, over‑current, over‑temp, and short‑circuit—worked as advertised in my abuse tests. A direct short trips the supply promptly and cleanly.

Connectors and the splitter

The connector kit is where this adapter earns its keep. A few highlights:

• The 5.5x2.1mm plug on the adapter body is the de facto standard and works directly for a lot of gear without an extra tip.
• The included reverse‑polarity coupler is invaluable for center‑negative devices (some guitar pedals and certain consumer gadgets).
• The screw‑terminal tip is a great add‑on. It makes quick work of prototypes or odd connectors without soldering.

The 1‑to‑4 splitter is convenient for low‑draw devices like cameras or LED accent strips. But the wires on the splitter are very thin, and the total current limit of the supply still applies. As a practical limit, I keep the total under 2–2.5A and try not to pull more than ~0.5–0.7A per leg to keep voltage drop reasonable.

A special caution on the USB‑C tip: this adapter does not negotiate USB Power Delivery. Many USB‑C devices expect PD handshaking; powering them with a raw 5V (or worse, a non‑5V setting) over a C plug can be risky. I only use the C tip for simple loads that I know accept 5V dumb‑sourcing, and I never use it at other voltages.

Safety and practical use

Beyond the built‑in protections, a few practices make this adapter safer and more predictable:

• Always set voltage with a meter under load if the target device is sensitive or draws over ~1A.
• Mark common set points (5V, 9V, 12V) on the case or keep a quick reference card.
• If using the splitter, check that combined draw does not exceed 3A and that each device still receives adequate voltage.
• Observe polarity carefully. The LCD shows voltage, not polarity; the reverse adapter flips it, so double‑check your chain.

For indoor use, the supply is quiet and doesn’t introduce RF noise into nearby radios in my testing environment.

Where it shines

• Quick bench work for small electronics
• Replacing lost or mismatched wall warts
• Powering LEDs, routers, small pumps, and microcontroller projects
• Testing devices across multiple voltages without changing supplies
• Running a couple of low‑draw devices from one outlet using the splitter

The flexibility and the accessory bundle make it easy to keep projects moving without hunting for the right barrel size.

Where it falls short

• No voltage lock. Bumping the knob can be costly on sensitive gear. A detent or push‑to‑turn design would help.
• Display precision. The readout is good for ballpark settings but consistently reads a hair high on my unit.
• Cable gauge. The output lead (and especially the splitter) introduces noticeable voltage drop at higher currents. That’s typical for this class, but it’s something to plan for.
• No storage case. With 14 tips and extra cables, a pouch or organizer would prevent the inevitable stray connector.

If you need rock‑solid regulation, low ripple, sequence control, or current limiting, a proper bench supply is the right tool.

Tips for best results

• Verify under load: Set voltage with the target device connected and a meter in parallel. Increase slightly to compensate for cable drop if needed.
• Secure the setting: A small piece of painter’s tape over the knob keeps it from drifting.
• Label the tips: A fine marker or small stickers on the most‑used connectors saves time and mistakes.
• Mind USB‑C: Use only at 5V for known “dumb” loads; avoid powering phones, laptops, or PD‑expecting devices.
• Stay under 80%: For continuous operation, target under ~2.4A or ~55W to minimize heat and extend life.

The bottom line

The Wefomey universal adapter is a practical, flexible tool that earns its space on a hobby bench or in a household toolkit. It doesn’t replace a laboratory supply, and it has quirks—no voltage lock, modest display accuracy, and thin cables that drop voltage at higher currents. But it starts cleanly, protects itself when misused, and comes with the adapters you actually need, including a polarity reverser and a screw terminal tip that simplify real‑world use.

Recommendation: I recommend it for hobbyists, tinkerers, and anyone who frequently needs to power small devices across 3–24V without a dedicated brick. It’s a great “Swiss Army knife” supply for testing, temporary setups, and light multi‑device duty. I would not choose it as a permanent supply for high‑current, low‑voltage loads or for critical equipment that demands tight regulation. Used with a meter and a bit of care, though, it’s an excellent value and a genuinely useful addition to the bench.