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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15 views

61000-3-2 Pre-compliance harmonics

I am wondering about 61000-3-2 current harmonics pre-compliance test. Say a company designs a single-phase [up to 13A] power converter for low-line 115V and high-line 230V and pass 61000-3-2 pre-...
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25 views

DC Coaxial Power Connector Rated for 20A

I have a 12V 20A power adapter seen here (https://www.ledwholesalers.com/v2/index.php?route=product/product&path=40_117&product_id=999). I would like to connect to this power supply, but my ...
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1answer
46 views

Altium->Coupled Inductors

Im glad to be with you. I have question about coupled inductors in altium. I want to make a flyback converter and tried first as in Image 1 . I converted 310V DC to 12V DC as you can see. I wrote ...
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2answers
60 views

how to transform 120V AC to 5V DC 5A load using flyback transformer circuit? Setting frequency - low cost, low footprint - change load capacity

i am using a flyback transformer circuit to keep the footprint small and cost efficient. Its been suggested to me to keep the frequency high so the transformer can remain small. how is the frequency ...
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4answers
42 views

Movement of electron in ac current

Movement of electron direction in ac current is continuously changing which leads to more collision of electrons then dc current.From this can we conclude that ac current heated the wire more than dc ...
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1answer
93 views

Transformer overheating reasons

I am currently designing a Flyback-based offline AC/DC converter similar to the following schematic (with a few changes e.g. sync rectifier at the output). Everything works nicely but the custom-made ...
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26 views

Converting 110V AC to 12V DC [duplicate]

I am currently moving to a location for work that has a 110v electrical connection but no water connection. I was attempting to use an RV water pump in order to create a plumbing system for my sink ...
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26 views

Redundant power supply out of two Recom RAC20-05SK

I know that there are plenty of questions regarding redundant power supplies, but mine is a little bit special: I am building an IoT Device running on 5V 4A DC and I am planning to use the Recom ...
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16 views

Webench coil selection for UCC28634DR AC-DC converter

I have being trying to design an AC-DC adapter for a freezer project I'm working with. After a couple of days researching I came across Texas Instruments Webench, which helped a lot. Although most of ...
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1answer
42 views

AC to DC conversion using without neutral

I have a project to replace my wall switch with my smart switch which can be controlled by ESP32. Needed to use AC to DC conversion to get 3.3V from 240V/50Hz. Some of the walls have only phase and ...
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1answer
45 views

Designing a triac based regulatable DC supply

I need about (30V-160V)32A DC for my project. I am trying to build an electronic circuit to regulate AC mains (220V, 50Hz) to produce voltage from 30V to 160V and rectify it to produce DC voltage. ...
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1answer
29 views

Terminology of AC -DC converters

I would like to ask about the difference between the terms "AC-DC Converter", "DC-AC Converter" and "Inverter". If I am getting it right, the "AC-DC converter" converters AC voltage to DC. The "DC-...
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2answers
106 views

AC-DC High voltage converter

I don't have much experience with power electronics but I'm trying to design a power supply with AC 220Vrms (311peak) to DC 1500V converter to charge a capacitor in 50 miliseconds (and keep charging ...
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1answer
50 views

Three-phase rectifier for offline single-phase supplies

First thank you for the help. I'll try to explain my self for this problem and sorry in advance if I'm not very clear, english is not my native language. I'm making a universal PCB design involving ...
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1answer
87 views

Flyback AC/DC based on UC28881 - TI's reference design - not working

I have build the AC/DC flyback converter according to TI's reference design but ist is not working and I am wondering why. By the way: I have build the 5 V version, so everything connected to T1:9,7 ...
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2answers
72 views

Step down transformer alternatives

Does anyone know if I can use a Quam TBL 25 volt 4 watt audio transformer to step down 120 volts to 12 volts, later to be rectified to a 12 volt dc power supply? I know 12 volt power supplys are ...
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1answer
73 views

What is the power consumption of a 12V adapter running 4 CPU fans?

I have a quick question here. I am not a ECE guy and just a hobbyist trying to tinker while quarantined. I have 4 CPU fans (120mm) laying around and I'm trying to re-purpose them as a small fan. ...
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0answers
29 views

Techniques for measuring the ripple current of SMD electrolytic capacitors

I am currently creating a test plan for an AC/DC converter (90VAC...264VAC -> 12VDC) I've been working on. Since the output electrolytic capacitors are of SMD type, I am trying to come up with ...
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21 views

where to find exact definition of i/p and o/p as used to define insulation resistance for AC DC converter?

Most AC DC converter datasheet use I/p and O/P to define insulation resistance I am looking for the exact definition of these parameters as used in this context ( I know their definition for ...
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1answer
62 views

What does it mean for a power supply to have an output range?

I had a power supply blow and I replaced it with one from the same company with the same model number. The new supply has lightly different specification than the old supply. Oddly (to me) it gives ...
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1answer
48 views

Full charged 12V battery with AC converter “empty” within one second - voltage drops, converter beeps

I have the following setup for solar power, which worked well until recently: solar panel <--> solar charge controller <--> small (car) battery <--> converter: 12V DC to 220V AC <--> my ...
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0answers
37 views

Need help wiring a power supply (UK)

First time here so apologies if this question is in the wrong place. Also i'm a bit of an amateur with this sort of things to go easy on me. I've bought a power supply to power a DC charger for LiPo ...
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30 views

Use old battery pack charger as DC power supply?

I have an old charger for NiCd battery packs. It is labeled with: Input: 230 V~, 50/60 Hz, 33 W Output: 4.8 - 12 V DC, 1.4 A I opened it and found a transformer and two circuit boards. I made a ...
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2answers
122 views

AC TO DC Converter IC

I am using a small circuit which needs 5V DC input and total current consumption of the circuit is 300mA. I have been using the small size ac to dc converter modules, but now i am searching for a ...
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1answer
47 views

AC-DC Switching Power adapter Unstable Voltage [closed]

I recently bought a AC-DC (14V DC, 3A) Power Supply on eBay to power a Samsung Monitor, and it does power on my monitor. It is not the monitor because another power adapter I have works with it. ...
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3answers
103 views

Powering small DC load ( 1W ) using 220V AC supply

I am trying to design a small control circuit for controlling large currents (not too large, around 200W, AC 50Hz). I have kept in the AC circuit isolated from the DC control circuit. But the problem ...
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2answers
163 views

Is It Posible To Have Step Up Power Supply Without a Transformer?

I am trying to design a high voltage low current power supply. My purpose is to design it without a transformer. For example circuit like this : My input is 220V AC after this circuit I am going to ...
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1answer
94 views

misunderstanding of Voltage output of a 3-phase rectifier

I simulated a 3 phase rectifier : I obtained V1 and V2 as plotted below : I dont understand that waveform as i'm supposed to obtain a DC voltage. Can someone explain me how it comes that i got this ...
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0answers
46 views

How to ground external AC voltage (18V) to Arduino?

I have a project where I need to read 0-18 Volts AC in Arduino's input (0-5V DC). So I did a circuit with a diode (half wave bridge), voltage divider, and a RC circuit where I tested some values for ...
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2answers
72 views

Positive and negative rail for op amp circuit

I need a positive and negative rail to power an op amp Since it's an op amp for a voltage reference, would using a circuit like this one be enough? Input voltage is unregulated 37 volts, with 4.7k ...
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3answers
276 views

Discrete linear voltage regulator

I am trying to make a discrete component linear power supply. This schematic seemingly works but it doesn't work when I build it on my breadboard. I am taking 110 volts through a transformer down to ...
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1answer
82 views

AC to DC conversion: is this an appropriate implementation?

I understand that a 20v AC converter supplies 20V RMS AC. I wish to convert this to 20v DC and so have drawn up a schematic for this which includes: the AC to DC conversion, regulation, smoothing, and ...
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1answer
46 views

Output current and voltage levels regulation in ac/dc adapter

On the picture below is the output circuit of AC/DC adapter. I understand how voltage level contol works, but I don't understand how exactly current limitation works and how should I calculate ...
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2answers
39 views

Is this a reference of an AC/DC REGULATED adaptor?

I need to choose an 230 VAC / 12 VDC converter which is regulated, that-is-to-say I need the voltage to be 12 V with a current of 0 to 5 A. I found this one because it is the cheapest (price really ...
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0answers
109 views

Flyback converter with dual outputs (12V / 5V)

I came across the following flyback converter circuit, which has a dual output (12V and 5V), but I am unable to figure out why the secondary windings are connected in series. Based on the datasheet ...
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0answers
57 views

Energy Meter power supply advice/help

I've been assigned to start working on a smart energy meter project, it's been like 10 years since I put any work in AC. I would be sincerely grateful for any constructive advice. Now the 3-phase ...
34
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3answers
6k views

Computer power supplies usually have higher efficiency on 230V than on 115V. Why?

As seen here in the example, this particular power supply (and most others too) has higher efficiency when running on 230V. Given that computer power supplies are usually required to output a ...
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1answer
74 views

How to choose AC/DC adapter - high voltage low current vs low voltage high current

I got an LED light kit, 2 lights, each takes 60W, at 12-30V. I'm planning to use these lights separately, and need to choose between: 12V, 5A adapter 24V, 2.5A adapter Both will give me 60W, but ...
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2answers
55 views

How do I safely connect a light switch button to the secondary side on a board?

I designed a special light controller board. It has a primary side that is connected to AC 230V. There are a certified AC/DC converter module and a relais, bridging the air gap between the primary and ...
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0answers
33 views

Can I use AC voltage from myRIO to power stepper motor?

I am using easydriver and arduino for a stepper motor provided on this website The motor is 17HS3401S Stepper Motor and I think this is the correct datasheet found on the internet for the same. ...
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2answers
74 views

Laying out power electronics on analog signal board, practical advice

to keep this brief I am designing some audio circuitry and also need to design the power supply. The barrel jack in the schematic below sees 18VAC and I am converting that to +/-15V DC rails. So to ...
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0answers
45 views

Power Supply Design 230 AC to 80V DC - multisim and real components

I am an young student that was tasked to build a power supply which will convert single phase 230V AC into 80V DC to test specific DC motors (custom made). I only know that under normal operation and ...
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1answer
36 views

Protection circuitry for AC/DC converter

I'm using the RAC02-GB (Datasheet) as an AC/DC converter and I'm confused about the protection circuit they included in the datasheet: I want to make sure the AC/DC converter has the proper external ...
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0answers
70 views

Why does rectifier output is showing DC instead of pulsating DC

I am using below circuit for PFC. Before connecting coupled inductor's auxiliary output to the IC's Vcc, I wanted to make sure that it is coming properly or not. So when I probed the red dot in the ...
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2answers
72 views

Determine the resistor required for a circuit [closed]

If I want to supply power to a device that is rated for about 2V using a DC source of 12V. How can I find the resistor o should use.
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2answers
111 views

AC/DC Converters in Series with the Same AC Source

Would it be safe to connect two identical AC/DC converters in series if they share the same AC source? My concern is that the negative DC output is grounded somewhere in the converters causing the ...
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2answers
49 views

Can this receptacle power this power supply? [closed]

My car has a wall-style AC receptacle in it. It is merely marked 110V 150W. It is not mentioned in the owner’s manual. I’m curious if it can safely power this laptop power supply:
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0answers
75 views

PFC boost converter is not stepping up the voltage

I am making a PFC circuit for AC-DC converter. I am facing a weird issue. As per my design the output of the circuit should be 390VDC, but I am getting 311VDCrms with ringing (overshoot 360V, ...
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4answers
1k views

Converting 8V AC to 8V DC - bridge rectifier gets very hot while idling

I am tinkering with an Arduino and recently had to convert 8V AC to 5V DC in order to run it. The project is a custom doorbell, which gets the power from the doorbell transformer (transformer is ...
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0answers
36 views

AC adapter won't power fan at full speed [duplicate]

I have a spare 92mm case fan rated 12V and ~600mA I've used to build a solder fume extractor. When I was prototyping it, I tested the fan with a 12V 2.5A AC adapter and it worked fine, ran at full ...

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