Questions tagged [ac-dc]

Questions regarding the safe and effecient design and implementation of AC voltage to DC voltage supplies. Typically Mains to some lower DC voltage.

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1answer
133 views

Equivalent sequence/stepper relay to “FINDER - 20.21.9.012.4000”

I am currently looking at this relay: FINDER - 20.21.9.012.4000. Which is step relay, that makes contact AC output active with coil input DC (12V) [which i need]; and disconnects output when coil is ...
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2answers
6k views

BeagleBone Black - power supply sensitivity

I've bought a AC/DC adapter which per its specifications should output 5VDC and deliver 3A. I was going to use this adapter to power my BeagleBone Black (BBB) with. However, when I'm measuring the ...
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2answers
521 views

Converting 28VDC -> 14VDC at around 200A How do you pull that off with that kind of current?

Current boat has 110AC air conditioners and some small appliances but the rest of the systems are on 12VDC. Genset ate a jellyfish and has to be replaced, so I'm working out options to upgrade/change ...
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0answers
238 views

What controller for a 400W AC-DC SMPS?

I would like to build a big AC-DC SMPS. I built a little one based on ST's VIPer22A. This is a nice little IC that can give up to a couple watts (my design was 5V 1A). It was easy enough to design ...
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1answer
6k views

Using an AC Fan on DC Battery

I have a 30wp solar panel which charges a 28amp 12 V dc battery. Can I use an ac fan (with less power) on that battery? I am newbie to electronics.
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4answers
2k views

home socket with DC voltage

I'm wondering why, in a standard house, instead of using many low power AC-DC rectifier, there isn't a big (like 12V 20~50A) AC-DC rectifier which supplies some wall socket with a DC voltage? In the ...
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4answers
673 views

How do I get a digital signal from a switch? [closed]

I want to essentially drive a relay using a switch. For eg: If the switch (AC Voltage : 220v, 50Hz) is switched on, it sends a digital signal to the relay to switch off.
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4answers
7k views

220V AC to 12V DC transformerless and main isolated converter?

I am trying to build a 220/12V AC/DC max 100mA converter without transformer. I tried so much and burned some circuits. at the end I decide to write here. I searched but couldn't find and answered ...
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1answer
223 views

Having Two AC-DC converters in series

I have two AC to DC full wave rectifier converters and want them to be in series to increase the voltage. The circuit is basically a generator going into a wave rectifier then a capacitor and resistor ...
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3answers
2k views

no-load voltage on ac-dc adapter

I recently acquired a toy that uses this transformer: but since I live in a 220V area, I cannot use it directly. I have this generic AC-DC adapter: which in theory is all I need because it has a 4....
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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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2answers
6k views

Switching between AC and DC input

Let's say I need to power a 9v device with an input power source that is either AC or DC and changes almost randomly. Is there any way for me to detect in a circuit when AC changes to DC or vice-versa ...
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2answers
653 views

Coil-less AC-DC line regulator

I'm trying to fix an AC-DC line regulator that I have build and doesn't work as expected. I'm trying to convert AC 220V mains to DC 5V 10mA without a transformer. To do this I'm using an 1uF 250VAC ...
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2answers
1k views

LED blinking array using LC-circuit

Basically I want to create a blinking unit to drive my LED's. The LED's are used to be driven at a frequency of ~1.5Hz (that made me choose the values of L and C). So here is my schematic. (I am ...
2
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1answer
4k views

Does a bridge rectifier care that much for AC frequency?

As I understand it, a bridge rectifier is a set of diodes that play a trick of logic that keeps the polarity positive. So, within the context of a household DC transformer does it matter what the ...
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3answers
4k views

Powering 28 LEDs in series by 220VAC - simple stabilizer

I have a home-made thingy that I would like to use as a lightning in my living room. It contains 7*4=28 LEDs (red, 1.86V, ...
7
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3answers
49k views

AC adapter: Input power vs Output power

When I look at, let's say an iPad AC adapter, the input/output rating on the charger states: Input: 100-240V 0.45A (AC) Output: 5.1V 2.1A (DC) I know that the ...
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3answers
396 views

Picking an AC-DC Converter to Minimize Cost [closed]

I'm trying to design an AC/DC converter to implement into a project I'm working on. The project needs to be isolated from mains and shouldn't require more than 1A at 5V. My question for you is what ...
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2answers
2k views

Thinking about LED light bulbs..as full wave rectifiers

Tw questions on LED bulbs. First Qt: Just something I was wondering. Since LED's bulbs are, by definition rectifiers ( I believe they are full wave) would it be possible to use them as such by putting ...
3
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2answers
4k views

Why have atx power supplies need selector voltage?

I am studying various ATX power supplies schematics and don't understand the need of the voltage selector as switching power supplies work at range of voltages. In most schematics i see the 110V line ...
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1answer
173 views

Wiring different DC voltages to use 120V AC

I apologize in advance if this is simple. I've only had an intro to circuits class and all we did was analyze existing circuits, and even that's been a while. For a design project I'm trying to wire ...
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1answer
3k views

Can I use the output of mobile charger as a DC source for my circuit?

The title explains it all. Can I use the voltage and ground pins from the mobile charger and use it in my breadboard circuit? Is it safe? If it isn't, what is the thing I need to buy so as to convert ...
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6answers
4k views

How can I run a 7.2VDC battery-powered drill off a 220VAC wall socket with limited part availability?

I have a battery drill, but the battery is useless, so I want to power direct from the outlet. I need convert 220VAC to 7.2VDC @ 4A. I can't use a transformer because the high output current, it ...
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1answer
1k views

Step-down transformer AC to DC voltage conversion problem?

I got a step down transformer from an old black and white CRT TV that is about 18v 0 18v, 10A AC current output. I wanted to convert AC to DC, so used four 1N4007 diodes as a bridge rectifier. When I ...
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2answers
134 views

which ac-dc adapter work with my device? [duplicate]

lets say I loose the acdc adapter of a device, like a laptop or a wireless router, how do you know that another adapter will work with my device? my assumption is that I have to match the same voltage ...
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4answers
11k views

Making 12V DC from 6V AC

I've got a 1980 Honda XL 185s that has a 6 volt electrical system. The headlight uses a 6V AC, 30 watt bulb powered from the generator. The other lights (tail, blinkers) operate off of the 6 volt ...
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1answer
1k views

12V 1A DC input filter

I have to design a power input filter of consumer device. It is powered with desktop AC/DC 12V power supply. Max current consumption - 1A. Device has a full metal enclosure. I am considering putting ...
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2answers
447 views

convert ac to dc circuit [closed]

I want to build real circuit, which converts AC signal to DC. AC signal looks like below: Its period T is about 2 seconds. At the output I want to get DC as shown in the right graph with voltage ...
2
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3answers
5k views

Can I use a 3-wire AC adapter in a DC circuit?

I am reading through the excellent book Make Electronics and am in a chapter that suggests getting an AC adapter, cutting off the connector at the end and stripping the rubber outer coating back to ...
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2answers
8k views

DC Adapter on AC Adapter Speaker [closed]

i've Speaker with woofer requiring AC 12 voltage, and i have DC 12 voltage Adapter. However, speakers are working properly. but Can i use DC 12 V Adapther with the Speaker which is requiring AC 12 ...
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1answer
296 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 ...
32
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2answers
1k views

If we could start our electrical grid from scratch with today's technology, which would be the most efficient choice? AC or DC?

Lately, I’ve been reading about the many advantages of HVDC transmission systems for long distance transmission, undersea links, and others. The historical reason of why AC was picked over DC was ...
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2answers
20k views

Converting universal AC to 3.3v DC @ 0.1A

There's a bunch of topics around this but i haven't found something that fits my requirements. I'd imagine this is a fairly common thing though so any pointers would be appreciated Basically i want ...
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2answers
2k views

Smallest AC to DC converter [closed]

What is the smallest cheap AC (110v) to DC convertor available for Arduino. I want this to be embeddable in a box along with Arduino without taking more space. Thanks in advance
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3answers
3k views

BJT Pre-Regulator

I have a circuit that has an input of 35V peak and I would like to drop the voltage down to 5V 200mA. I was recommend to use a pre-regulator in the following configuration: The good thing is that it ...
2
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2answers
559 views

Electrical circuit / transformer in series?

I would like to pull out 5v 3A max in series from an already existing connection from the mains 240v 40A connection. Current circuit: What I would like to implement: What are the possible problems ...
34
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3answers
130k views

Help me understand the relationship between positive, negative, neutral and ground in AC and DC

This question stems from notations on schematics and seemingly conflicting information I'm seeing. I suspect that I'm seeing different vernacular for the same concepts--but I'm in a place where no one'...
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2answers
8k views

How to use a transformer to power a 5V chip (an Atmega328)?

I am designing an Atmega328 based device which needs to be powered directly from 230V AC. I have found a transformer in my local electronics store which seems perfect, but I have never worked with ...
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4answers
1k views

Dual AC feed to power a DC unit (Raspberry Pi) with Diode and Polyfuse for protection

I wish to place some Raspberry Pi's in remote locations (data centres) for telemetry and other services like serial OOB access. Typically dual AC feeds are presented to customers in a data centre ...
5
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2answers
8k views

Calculating the True Power Factor in non-linear loads

In my circuit I am taking in 60 Hz 120 VAC from the power company and hooking it up to a AC/DC non-linear switching buck converter I am designing. I know that: true power factor = (displacement power ...
5
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2answers
4k views

Is PFC compulsory for AC/DC converters 75W and above?

I’m reading the user guide for a Microchip reference design of a 300W AC/DC converter. Section 1.2 starts with these requirements: A conventional SMPS must implement PFC if it draws more than 75 ...
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2answers
9k views

How can I Build a Full Bridge Rectifier?

For further detail, I plan to extract an alternating current and convert it to direct current. Suppose that the AC flowed through the wires; how can I make it a direct current using the full bridge ...
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8answers
7k views

Is it safe to use a DC power adapter that isn't UL Listed or CSA certified?

I picked up a 9V switching DC adapter from SparkFun a while back, but I've been hesitant to use it because it doesn't have any of the usual "safety" approvals that you normally see on power adapters (...