DigiKey performs a $17 bench power supply teardown #PowerSupply #Safety @Digikey

Digikey documents a thorough analysis tearing down and analyzing a $17 Best model PS-1502DD power supply.

The old axiom “you get what you pay for” is often invoked in discussions of product quality.  It can also inspire curiosity as to what exactly one does get when the price paid for a product is significantly less than asked by others having comparable basic specifications.

It was this spirit of curiosity that led a colleague to purchase a bench-type adjustable power supply, advertising a 0-15V, 0-2A output from a low-cost supplier for all of $17 USD.  What exactly does that buy a person?  Let’s find out.

After completing this write-up, it was found that this same supply is available under maybe a half dozen different brand names, at price points ranging from the $17 USD range mentioned to upwards of $50 USD.  Numerous resources are available demonstrating the basic functionality of the device; this article focuses more on reasons that a person might want to consider spending more on a device of this type.

The standard tests are performed first including output voltage and current and safety tests. The ground was not a true earth ground as the non-polarized European 220V plug had no ground connection.

Testing showed some prominent safety concerns:

(The unit has) single-line fusing in conjunction with that symmetric, reversible AC input plug.  There’s only a 50/50 chance of the fuse being connected between the “hot” line and the appliance, so should an AC-to chassis fault occur, there’s only a 50% chance that the fuse would be in a position to provide any protective effect at all.  In the case where the plug is connected so as to put the fuse in series with the neutral AC conductor, the fuse opening during a fault condition might actually cause an increased hazard, since its doing so would eliminate the only “safe” current return path available.  The diagram at right shows the path of current flow should an AC to chassis fault occur in the supply in question.  Note that the fuse isn’t even part of the current path in this scenario.

Digikey dives into the ripple and other electrical characteristics. They also find some decent features.

See the whole article for their findings.

Editor’s Note: In the Adafruit store, Engineer Limor “Ladyada” Fried has personally tested all items, especially electronics like test equipment, to ensure they meet her strict standards. Shopping the Adafruit store provides the company assurance of quality and performance.

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in! adafruit.com/mastodon

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – The easiest way to program microcontrollers – CircuitPython.org

Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.