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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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Wall-warts and power supply current capacity

How are some of these power supplies in consumer electronics (wall warts) able to achieve output ratings of 9V @ 3000mA with such a small footprint? I know surface mount components can help with this ...
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2answers
64 views

Confused as to why one USB battery pack will run my devices vs why a wall wart will? [closed]

I am trying to run a 5 Volt 4 Amp Item off of a USB Power, and something went wrong today that I wouldn't have expected. For reference, I am using a USB cable capable of sending 2.4 Amps, and either ...
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2answers
475 views

wall adapter/battery select circuit

I have a wireless keyboard that I would like to power through a USB cord, I am not a fan of wireless, especially due to the battery use. I would however like to have the possibility of having the ...
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1answer
104 views

12V wall wart down to 5V [duplicate]

I'm trying to take a 12V wall wart supply down to 5V @ 0 to 500mA without using a prebuilt regulator. I was thinking to use a voltage divider setup but after doing calculations I would be using 2, 12 ...
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2answers
246 views

Oscilloscope measurements on device connected to a AC/DC wall-plug

I had a discussion with my colleges regarding Oscilloscope measurements and DUT (device under test) isolation. Specifically a device connected to a AC/DC wall-plug. I think I am aware of the concepts ...
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1answer
109 views

Need to create -5.5/+5.5 and 25.5VDC from 12VDC wall wart

I'm looking for a cost efficient way to create +/- 5.5v and 25.6v from a 12VDC wall wart supply. The product I'm working on will probably use a DC wall wart so I need a solution that will work with ...
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1answer
93 views

DC Jack Adapter for 5V 2A Wall Wart

Below is a wall wart with ratings 5V 2A. I'd like to buy a DC adapter of some kind for this wall wart, so I can easily wire things to a circuit or bread board. What is the name of the DC side of ...
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1answer
93 views

120v 60hz 8w input, 6 v 800ma mains adaptor, what is the equivalent here in oz on 240 v? [duplicate]

Title says it all, Ive got many an adaptor lying around, do I need another 6v .8a at 240v? I should note ive had it plugged into the mains with a standard international adaptor for over three years ...
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2answers
1k views

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 ...
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1answer
8k views

What does it mean when a charger has 5V 0.7A?

For my phone (Samsung Galaxy Note 2) I have several chargers. I noticed that with some of them it takes much longer to charge the phone, to the point that a whole night is not enough to charge it. So ...
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2answers
113 views

35W 6V, what wall wart max current needed

If I have a load of 35W at 6V. (5.8A). How would I scale up the current to 230v UK mains voltage? I am doing this to decide what wall-wart to use (and what max current specification to choose)
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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 ...
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3answers
2k views

Correct way to measure a wall wart voltage [duplicate]

I got a full drawer of second hand wall warts which I'm planning to use for powering arduino projects (mostly 5V "pro mini" or "nano"). I'm using a voltmeter to check that they are still working, ...
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2answers
113 views

Modifying Wall-Wart for 5.5V [closed]

When I use my tablet on my balcony I would like to have it connected to the charger, but using a long (3m) USB cable seems to drop the voltage so that it doesn't charge. I am wondering whether I can ...
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1answer
97 views

Automatic distinction between PC-USB and Wall Adapter-USB

I want to ask if it's possible and an advice on how to make an automatic distinction between an PC-USB port and Wall-USB adapter. I've a battery charger IC (for example http://www.mouser.com/ds/2/405/...
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1answer
371 views

no-load DC output voltage of DC wall-wart circuit

I have this question and I believe the answer is 12.73 from the equation V(N) = V(Rated) * sqrt(2). Is this the correct formula and can someone show me how we arrive at it if it is. I am unsure ...
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1answer
309 views

Use indepenent power sources for Arduino and for breadboard

I am building a breadboard circuit to be controlled by Arduino. The circuit consists of about 20 bright leds simulating a vehicular lighting system (ten leds for headlight, 4 in taillight, 3 for each ...
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1answer
1k views

Why are some AC/DC adapters light while others are heavy?

I was browsing the thrift store and found a nice pair of JBL 2.0 computer speakers, but they lacked a power adapter. They call for a 12V 1A supply. I have a ton of "bricks" lying around, but no 12V ...
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3answers
1k views

Switching between two sources of power to a battery?

This is the simplified system: a battery (3.6 V, 2450 mAH, NiMH) a solar panel (max 5.2 V, 157 mA) a wall charger (5 V, 2100 mA). The battery is constantly being drained, but very slowly (85 mWh per ...
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0answers
90 views

Calculate number of LEDs, and resistor values, when some is turned on/off from time to time?

The LEDs that I have available is 3.2V ~ 3.4V and 20mA (exLED 5mm LED). (i'm planning to use the clear ones). The resistors is 1/4W metal film resistors (1/4W Resistance Metal Film Resistors). And ...
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1answer
915 views

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 ...
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3answers
353 views

Mixed analog-digital power supply

I'd like to build a project where I'm essentially controlling analog signal generation in the audio range from a microcontroller. In other words, an analog synth with digital control. I'm at the stage ...
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6answers
17k views

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 ...
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1answer
183 views

Electrical part question

Does anyone knows the name of the part that connects with this power adapters cable?
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2answers
3k views

300 amp 12vdc power supply on a standard(American) wall outlet

I am building a project that will draw around 300 amps at 12vdc, for about 40-60 minutes then it will rest for a few minutes. For this projects application it will be very impractical to build a ...
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1answer
295 views

USB host power dc/dc converter chip [closed]

I'm looking for a (cheap, surface mount) single-chip dc/dc converter to power a USB connection. I'm thinking that with so many USB chargers available, there might be a chip available specifically ...
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1answer
236 views

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 ...
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5answers
62k views

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 ...
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5answers
2k views

Is there a standard DC power jack that prevents devices from being damaged by the wrong voltage? [closed]

USB is by far the most widely used serial bus by consumers. Plugging any device in any USB port is safe from hardware point of view. On the other hand, the common DC power jack . For example this guy ...
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1answer
4k views

Dual power supply from a single AC adaptor [duplicate]

I designed a microphone preamplifier based on a single op-amp. It works perfectly using two 6-volt batteries. However, I need to power it directly from AC. I found a 9 V AC rated wall-wart, but it ...
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1answer
268 views

Powering my projects and breadboard

I have a few differant AC to DC converters and wanted to know a good way to use them to power my breadboard and projects once they make it to strip/protoboard. One adapter is used for laptops (Part ...
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3answers
2k views

How does power in “wall wart” power supplies work?

I'm new to electronics and am having trouble understanding how power supplies convert 120AC into a safe, manageable DC voltage. So far, I understand that there's a transformer to step the voltage down,...
2
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1answer
629 views

What happens when you dim a wall wart?

I am hooking a wall wart to a plug on a dimmer switch which is hooked to some LEDs and a resistor to create a LED "lamp." What will happen when I dim the switch? Will it reduce the voltage? The ...
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1answer
290 views

Is there a prebuilt PCB that does the equivalent of a wall wart for a similar price?

I am working on a project, and I need to convert 240V AC power to 5V DC to power a microprocessor. I can't use a wall wart, and I am looking for a PCB that will do the same as one - for near the same ...
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2answers
336 views

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 ...
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3answers
367 views

Is it safe to parallel wall-wart inputs via a single cable?

I have 4 identical devices each with their own low amperage wall wart, and I want to tidy up my power cabling. (They are more like laptop power supplies than wall warts, as they have an AC cable, ...
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1answer
243 views

How can I reduce the power consumed with wall warts?

I have been designing a project that requires a 5V for some components and 12V for others. I am planning to leave this plugged in 24/7 so I want it pretty efficient. I know they don't waste that much ...
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4answers
827 views

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 ...
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2answers
59 views

subsituting one transformer for another [duplicate]

Possible Duplicate: Choosing power supply, how to get the voltage and current ratings? I have an eliptical machine that is no longer being manufactured. it appears that the AC to AC adaptor that ...
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1answer
2k views

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 ...
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5answers
838 views

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 ...
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1answer
308 views

Powering multiple circuit boards from one wall wart

I've got two home-build Halloween props that currently run from multiple battery packs. I want to switch this to a single wall wart. Here's what I need to power: 1 arduino, 2 Cowlacious audio boards,...
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2answers
2k views

Switch mode power supply

I am currently using a 5V DC, 1 amp wall wart to my circuit which is on a PCB. The wall wart plugs into the PCB using a barrel jack. All in all, my circuit uses around 300mA and can take between 3....
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4answers
22k views

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 ...
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2answers
22k views

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 ...
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2answers
500 views

Wall transformer amperage

I have a battery charger that uses a 24VDC 300mA wall transformer. The transformer died, and the closest replacement I could find was 24VDC @500 mA. The new transformer did seem to charge the battery ...
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4answers
4k views

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 ...
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5answers
8k views

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 ...