Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [wall-wart]

Colloquial name for an AC/DC adapter where the AC pins and regulator circuit are combined within a single enclosure. Some other regional names include plug pack and power adapter.

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How much power is really wasted by a wall wart?

The title pretty much sums it up... Hyperbole aside, how much actual power is consumed by a typical wall wart when the device it's attached to isn't powered on? And are there designs for wall warts that minimize or eliminate this sort of parasitic…
Kaelin Colclasure
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How does this wall-wart switcher work?

UPDATE I've provided a full outcome report in one of the answers below with an updated schematic and description of the operating principles as I've come to understand it. I'm studying switching converters to feed a strange craving to understand…
scanny
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Least expensive way to plug in a microcontroller into 120V (without wall wart or batteries)

I need to be able to power a Atmega168 by plugging it into a wall. The circuit is a little bit more complex but not too much. The Atmega168 needs between 1.8V and 5V at 200mA. The ideal solution needs to be contained all on the PCB board. No…
Alexis K
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Converting passive USB Hub to powered USB Hub, by adding regulated wall-wart as power supply?

From a quick price-check on ebay, Passive (bus-powered) USB Hubs - ~ $2-$5 Powered (externally) USB Hubs - ~ $15-$20 My use-case is to expand the no. of USB ports on a ARM-based SBC, and to embed the hub in the same enclosure, so I was wondering,…
bdutta74
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Automatically switching from 9V battery to DC wall adapter on insertion

I have a simple circuit that runs off of a 9V battery. I'm re-designing it so that it can also run off of an external 12V DC source (ie: a wall adapter). I want to design the circuit so that if both the battery and the wall adapter are connected…
Cloud
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What to do when a device doesn't specify it's DC polarity?

This is probably a very simple question but.. I've been trying to find replacement AC->DC adapters for various electronics around the house, but I ran into one which doesn't list its polarity. It simply has "12V " printed next to the power socket,…
MrKatSwordfish
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Determining if a power supply is isolated?

I've been looking for a low cost adapter I can use to power some electronic circuits I'm playing with. Pretty much the only requirement I have at this time is that the adapter is mains isolated for my safety. However, I can't find any markings on…
helloworld922
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Advice on cleaning up 5VDC from a wall-wart

Assumption: I think it's generally true that commercially available AC/DC wall-worts can be expected to be pretty noisy (e.g. you can't count on much better than 5% stability). Background: I'm dorking around with an RF application right now, and I…
vicatcu
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Do I need to use any external parts with a voltage regulator?

I have recently bought a voltage regulator (link, specs, and datasheet below) and I am regulating a AC-to-DC 9v power supply into 5v with as little components as possible. In the datasheet, all of the diagrams use capacitors, and I don't have any on…
Anonymous Penguin
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Do phone chargers communicate with the phone?

I have come across multiple YT videos (about the new higher USB power delivery and battery degradation) mentioning that chargers communicate with the phone or laptop when charging to avoid battery degradation, or avoid supplying too high a power. Is…
SoccerFan
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Does appliance wattage differ by country, since the voltage does?

As an example, I have an AC-DC "wall wart" that specifies an input voltage of 100-230 volts and an input current of 0.3 amps. Since my mains supply is 230v: Does that mean that it uses 230*0.3=69 watts? If I were to use it in a 110v country, would…
Dataflashsabot
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How to power a circuit that needs +9VDC, GND, -9VDC?

While I have an assortment of 5V, 9V, 12V wall-warts, but I don't remember ever seeing one that is 18VDC and trying to avoid a trip to specialized parts shop, since I have all other components of a circuit (of a microphone mixer) that I am…
bdutta74
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Will this wall wart supply enough power?

I am building a little pen plotter. It is powered by a 12V 1.0A wall wart, as well as by a standard USB connection. There is an Arduino Duemilanove, which will draw 120mA for the Atmega328 as well as 50mA for the control pins. Attached to the…
Blue Ice
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Do 2 5V DC wall warts in the same AC outlet have a common DC ground?

I'm trying to power a LED strand from one wart (5V), and my logic driver FPGA from another wart (also 5V). Both warts are plugged into the same outlet strip. I know I should probably power them from one, but I don't have the plugs on hand to rig…
Tim
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Building a wall-wart style case

I'm working on a project that will plug directly into the wall outlet, similar to a night-light or a wall-wart power supply. Internally, I'll use a AC-DC converter like this one. It has built-in filters and has agency approvals. I'll add the…
bitsmack
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