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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57 views

How to hook a transformer to a outlet

I bought some plug ends to hook up to my outlet I wanted to connect the plug with some wires, I was told that I needed these type of wires I however wanted to use low voltage wires like these It ...
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3answers
81 views

Calculating 12v Battery Ah

Forgive the ignorance here, electricity is a weak point of mine and I'm trying to wrap my head around it all. I'm trying to find out how many Ah exist in an old lead acid battery. I hooked up an ...
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2answers
43 views

Rectifier design calculation

I am working on a rectifier design. For that I am analyzing the formula for capacitor selection. I came across a video reference. Io: average output current Vo: Average output voltage Vc: capacitor ...
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2answers
60 views

Off line 3V3 power supply with 3V3 LDO without a transformer

Attached is a schematics page from Microchip's development board. This question is only about the 3V3 power supply they use for powering their PIC circuit. Can someone minimize this schematic to the ...
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1answer
82 views

Can Earth be utilized as the whole circuit's common ground?

I'm currently handling a project that requires a transformer to step down 230VAC to 6VAC; and from there, further scale-down to a voltage that is in the readable range of the microcontroller (as not ...
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2answers
88 views

How do I wire up an aftermarket USB Type-C connector so that it works?

I recently broke the male port of my USB-C laptop charger. I already got a new one, but I would like to fix and repurpose the old one to be the power for my Raspberry Pi 4 instead of throwing it out. ...
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1answer
24 views

withstand voltage of AC DC power module

i read the datasheet of irm=20-5 which is a AC DC power module it takes a input of voltage of 85-305VAC and converts into 5V DC at output ,in the datasheet it is written that the withstand voltage is ...
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2answers
133 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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1answer
33 views

Power for 1 Device, 1 MCU, and 2 modules

I have four things I need to get power to. The first is a device that needs 48V and 30W. The other three include an MCU and two modules. Each have various pins that need either 3.3V or 1.2V. I’ve ...
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23 views

120/277VAC to 12V DC SELV

What's the go-to way to make 120/277VAC to 12V DC which is SELV compliant on a PCB? I know one option is to purchase an ACDC converter like the IRM-02-12, but it seems a bit expensive. I'm surprised I ...
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4answers
272 views

How can I run my e-bike wheel on AC power?

I have an electric wheel designed for an electric bicycle conversion. By my understanding, the wheel is essentially a 48V, 1000w rated brushless DC motor. It comes with a thumb throttle and kill ...
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2answers
196 views

Power Supply for two 50V/12.5A Solenoids

I'm in the planning stages of building a custom pinball table and one of the sticking points is powering the flipper coils. They're 50V DC coils with a resistance of only 4 ohms during the stroke. ...
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1answer
18 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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3answers
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 ...
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26 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
56 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
69 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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1answer
352 views

Different Wattage Solar Panels for Home [different Voltage/Ampere]

My current solar system for home 12V 100W polycrystalline Solar Panel. 12V 75Ah Lead Acid solar tubular Battery. PWM 12V 10A Solar Charge Controller. 12V Input and 200VA Output Inverter. Current ...
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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
48 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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0answers
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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18 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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31 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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1answer
49 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
30 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
108 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
94 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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1answer
62 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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4answers
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
79 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
89 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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33 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
49 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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1answer
63 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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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
158 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
51 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
204 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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49 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
74 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
379 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
83 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
48 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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125 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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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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59 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 ...

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