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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Understand firing angle chart in dual converter

How to understand below Firing Angle Chart, I guess the y axis should be voltage of the source, but what is the x axis, why a1/a2 points right, the location of 0⁰/90⁰/180⁰ seems quite strange. Hints ...
Lv Yaojia's user avatar
2 votes
5 answers
170 views

How can an AC adapter push 11A but only suck 2A?

I have a laptop adapter that takes in 120V AC and converts it to 20V DC. The adapter is rated for 230W (11.5A 20V.) Knowing conservation of energy and such, this means that the adapter takes in 120V ...
zapshe's user avatar
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Calculating input power of ACDC power supply

I'm trying to calculate the input power draw of an ACDC power supply that we are using in a control chassis and am confused by what to me looks like conflicting information in the datasheet. The power ...
Open_Hamster3337's user avatar
1 vote
1 answer
55 views

Ground connections around bridge rectifier in flyback converter

I am designing a flyback converter and I am being told to make the ground net connections as shown in the image below. I think this is colossally dumb because it eliminates PRI and SEC isolation. I ...
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esp32 s2 touch sensor read

I have a problem with capacitive sensor. I have created PCB with 2 capacitive sensors. Everything is working fine and ESP32 s2 mini reading values as I expect while I powering up esp32 with type-c 5v, ...
Ignas Navickas's user avatar
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1 answer
55 views

Seeking a good solution for mitigating the effects of high in-rush current caused by an AC-DC converter [closed]

Many AC-DC power supplies (say, 220VAC to 24VDC) have huge inrush current values. For example, a device might have an inrush current of 80A@230VAC. This raises the question of how to handle the ...
Dmitri Nesteruk's user avatar
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2 answers
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NiMH battery charging problem

I have a battery (8 cells in series, NiMH AA cells (1.2 V to 1.3 V), 1300 mAh per cell). Cells used- https://www.amazon.in/Rechargeable-NiMH-2300-Peak-Power/dp/B01MF8HUKO https://www.amazon.in/...
funtastic rdj's user avatar
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113 views

Is there a 3-phase to DC converter that draws current proportional to voltage?

Of course, 3-phase alternating current can be converted into a rippling direct current with a 3-phase bridge rectifier. This design only draws current from the two phases with the most voltage ...
Electric-Gecko's user avatar
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2 answers
70 views

What AC/DC adapter do I need to power 10 high-power (3W) LEDs?

I'm attempting to build a near-infrared (850 nm) lamp using high-power LEDs and am struggling to design a suitable way to power them directly from the AC power plug (220V). I have 10 high-power LEDs ...
vtot's user avatar
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5 votes
2 answers
2k views

Which power source is good for my project?

I want to create an inverter LED light source. I would be using 2 COB LED lights rated at 4 volt DC, 8 watt. My idea is that when the phase is connected, I want the light to glow and at the same time ...
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Single Phase Active PWM Rectifier using MOSFET

I am using this H-Bridge Configuration to make active PWM rectification to control the output average Voltage by controlling the Modulation Index. Here is the circuit diagram and the pulses of each ...
Saif 's user avatar
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AC and DC inputs to a Power Supply

I am studying about power supplies and I need some help with the following. I have a power supply with a 12 V DC output to power the lower power controller electronics. This power supply has two ...
power_electronics_engineer's user avatar
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108 views

How does an AFE boost voltage?

I have an active front end unit that is connected to a 3 phase system. It's controlled via software and I can set a value for the DC bus voltage. When the input is the AC 3-phase, how does this ...
Thomas C.'s user avatar
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3 answers
90 views

Transistor specs in the capacitance multiplier

I'm working on a constant current power supply and as a first step designed the following rectifier with a filter. I know the bottom rectifier is inactive, but with couple of switches the circuit ...
beardeadclown's user avatar
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105 views

How to convert 240 V single phase to 300 A 12 V DC

Residential situation with mounted 2-ton hydraulic 12 V crane. Have 120/240 available, need to create 12 V 300 A available power for intermittent use, boat launch. Average power used 150 A 12 V DC, ...
Brad R's user avatar
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Powering up an AC-DC power supply under load

Is it safe to power up a AC-DC power supply while it is connected to a load? Specifically what I'm trying to do is replace an AC espresso water pump with a 24V/2A Brushed DC water pump. Additionally a ...
Tate Mazer's user avatar
1 vote
2 answers
148 views

Full Bridge Rectifier Schematic Analysis

I am working on a circuit of an old 90's Terminal Applicator and noticed it has AC power coming in, then stepped down with a transformer, and then going to a pair of full bridge rectifiers. One goes ...
Erik Vincent's user avatar
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1 answer
159 views

Flyback converter MOSFET driver

I am building a flyback converter to convert 230V AC to 20V DC using a microcontroller. So far my simple converter works, but I have to power the MOSFET driver such as HCPL-3101 from a secondary DC ...
Amin Gholizad's user avatar
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3 answers
145 views

How are modern ACDC power supplies desgined?

I wonder about how exactly modern, but mundane ACDC power supplies (your phone power supply) are designed. Maybe my misunderstanding comes from one of the following assumptions: Modern AC-DCs ...
Niclas's user avatar
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Best placement of bridge rectifier to allow DC/DC convertor to become AC/DC convertor. Does this inhibit surge and EMI performance?

I am trying to use the power supply: CQB50W12-72S12 with AC power without degrading the performance of its recommended filter and surge components. 120VAC peak voltage is 169V and I am worried that ...
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2 votes
3 answers
452 views

PCB inside metal chassis. Is chassis ground required?

I have a project that has a PCB housed in a metal enclosure. The PCB is powered by a USB-C connector. Power input is 20 V DC @ 4 A max. Power is sourced from an isolated AC/DC wall wart adapter. The ...
Vulxcn's user avatar
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1 answer
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UL ratings and power supplies (DC transformer)

I read somewhere that if you sell a product that you plan to be UL certified, this means its power supply must be UL certified as well. This means that if you supply power via a transformer (external ...
user1584421's user avatar
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2 answers
93 views

ATX Computer Power Supply Spark in Non-computer Application [closed]

I would like to ask for your assistance with using a Silverstone DA1650 Gold computer power supply (you can find more about it here: Silverstone DA1650 Gold) for a non-computer application. In this ...
Gabriel's user avatar
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Safely run a pump using the driver/controller built into an air conditioner - switch EMC motor for a pump motor

I am attempting to switch an ultra-efficient household air conditioner from air cooled to liquid cooled. The unit, (LG DUALCOOL with Watt Control-Eco - T06EV4), was attractive because it has 3 power ...
SV Savannah's user avatar
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0 answers
73 views

AC adapter interfering with WS2812B LED strip

I have 2 power adaptors connected on same AC line, both grounded. Power adapter 1: 12V DC 10 A for powering 12 V LED strips, controlled by ESP8266, IRLZ44N MOSFET used to control brightness of the LED ...
m4X's user avatar
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6 votes
2 answers
936 views

Is an AC/DC converter with no visible fuse before the transformer inherently dangerous?

I've been using a generic, unregulated mains AC/DC converter (wall-wart) for a very low-power project. It's output was a bit prone to 50 Hz ripple, so I opened it up to investigate how the circuit ...
Wossname's user avatar
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1 answer
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DC appliances running on AC system [duplicate]

How do DC ran appliances work in an AC electrical system? For example, a house runs on AC, but the microwave runs on DC. How exactly is AC converted to DC? Does that DC power then have to invert back ...
Zach 's user avatar
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1 answer
205 views

Is there any benefit to converting from single to 3 phase AC before a DC conversion?

Compared to single phase, 3 phase AC produces less ripple in the resulting DC waveform when rectified. At the capacitor filtering stage, it is much cleaner with less sag than filtered DC converted ...
user148298's user avatar
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2 votes
3 answers
151 views

Trying to fix a mess with DC Power supply

I am not even close to know what I am doing with the electricity, but I have a power supply of my 8 cameras that is gone bad and I think I can manage to replace it myself, but there is a big BUT here. ...
Hristian Penchev's user avatar
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102 views

Should consumer electronics have low voltage isolation?

I am making a MCU (PIC12) controlled 230V relay system. They will be operated from 230V mains. Should I use isolation (1:1 transformer?). I would use this converter for 230VAC-5VDC (or something like ...
Ri Di's user avatar
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-1 votes
1 answer
152 views

AC-DC Schematic - Is this a Death Capacitor [closed]

Is this a death cap? I think it's not a death cap because it doesn't connect to the DC ground, but I'm not 100% sure. Image Source: Hi-Link HLK-20M24 Datasheet - https://www.rhydolabz.com/documents/...
Dan's user avatar
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PCB AC/DC Converter Circuit Protection - Australian Requirements

What circuit protection and other requirements are needed in Australia for a mains (220V) to 12V AC/DC converter on a PCB? If it's relevant, the loads are behind additional switch mode supplies which, ...
Dan's user avatar
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2 answers
368 views

Why aren't I getting a voltage reading from my AC/DC power adapter

I am new to electrical engineering. I cut the barrel jack off the end of a 24V DC power adapter, exposing a red and white wire. I'm trying to determine the polarity of the red and white wires with a ...
A__'s user avatar
  • 111
2 votes
2 answers
56 views

Non Fused AC Rated Disconnect Switche for DC System

I have 110VDC supplied by a controller to power a actuator/motor located in a hazardous C1D1 environment. I wish to install a disconnect downstream of the controller in the hazardous location so the ...
ThatGuyEE's user avatar
4 votes
4 answers
1k views

Predicting health of power supplies

I have a couple of 12 V, 1200 mA wall mount power supplies. Currently, using a digital multi-meter, I am able to measure good voltage and amps coming out of some power supplies. Since these are ...
khrissicks's user avatar
-1 votes
2 answers
167 views

Why do photodiode transimpedance amplifiers care about signal frequency?

I'm designing a circuit to amplify low light levels (in the range of 0.1 uW) of measured black body radiation for application in a pyrometer. I don't have much experience with this kind of stuff so I'...
Winston Wilhere's user avatar
0 votes
1 answer
75 views

What fire tests are done on power adapters/chargers?

I was curious about the fire risks in using a typical AC-to-DC wall adapter (e.g., this) and went to the UL website to learn what exact tests were done to get the "UL LISTED" stamp, but I ...
bobuhito's user avatar
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0 answers
92 views

Variable input 208V-600V AC to 24V DC without transformer

The Question: How can I design a circuit for an automatic transfer switch that accepts 120V-600VAC and keeps some 24V batteries charged (long term trickle charge is fine). P.S. I would like to keep ...
L. Bread's user avatar
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2 answers
87 views

What damage or reduced performance would result from giving 120 V, 60 Hz AC power to a 115 V, 400 Hz AC/DC rectifier?

This is part of a larger project, and is one sub-question related to a higher-level question I've asked on Reverse Engineering. You may find useful background information there. I have a controller ...
Eric Jackson's user avatar
0 votes
1 answer
93 views

My AC-DC PFC rectifier self-boosts voltage when with no load

I have made a PFC IC LT1249 reference design - a few differences are 820 uH inductor, 1.1 mF capacitor and different MOSFET. When I connect AC (50 V) with no control (17 V) voltage the DC output rises ...
Ri Di's user avatar
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1 vote
2 answers
856 views

Reusing a HP laptop charger of 3 wires (logic inside)

I have an HP laptop charger 18.5v 3.5A (1X2057... WBGST0A...) In the past the charger was working fine and I removed the tip for an experiment, so I can't check wires measuring the original tip. Wires ...
Daniel Perez's user avatar
0 votes
1 answer
224 views

SMPS for AC-DC conversion

The question is related to datasheet of part DK1203. The datasheet description is as follows: The DK1203 is a secondary side flyback type AC-DC Switch Mode Power Controlling IC. With integrated 700V ...
quantum231's user avatar
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5 votes
2 answers
602 views

What are the advantages and disadvantages of feeding DC into an SMPS?

Can I feed DC into an SMPS to get a regulated output? If yes, why? and What are the advantages and disadvantages? For example, I would like to input 200VDC to an SMPS with an input range of 100-230VAC....
Nithin's user avatar
  • 132
4 votes
1 answer
368 views

Help me make sense of this guitar amp relay circuit

Here is a channel-switching relay from a guitar amplifier. It is supplied with 6.3 V AC. Closing the switch (near center) operates the relay. It's on a schematic that's taped to my wall, and I started ...
Isaac Lubow's user avatar
0 votes
1 answer
71 views

Need to build a power supply from 127v AC to 3 DC outputs

I need to build a power supply that takes 127v AC and outputs 3 DC voltages: +90V, +1.4V, -4.5V. It is for a small tube amp, actually I'm powering the amp with batteries. I general terms, can you ...
Cristiano Sarmento's user avatar
5 votes
2 answers
611 views

Having trouble understanding textbook explanation of "hot chassis" in full-wave voltage doubler vs half-wave

The textbook explanation is not doing it for me. The half-wave voltage doubler shown in Fig. 4-27(a) offers some improvement in safety over the full-wave voltage doubler. Compare Figs. 4-24(a) and 4-...
Al T's user avatar
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2 votes
4 answers
238 views

Why does a "better" Schottky diode result in inferior AC-DC converter performance?

I have an AC-DC converter that outputs 6 A current at 12 V output. It's based on the CR6850 PWM controller. The schematic diagram is attached. I need to increase the output current to 10 A. The high ...
Isso's user avatar
  • 183
0 votes
1 answer
41 views

XL4016e1 maximum input current

I have an XL4016e1 dc-dc converter circuit, the output of the circuit is 12V 6 A . What should be the current value of the power supply to obtain this current? thanks
muhammed hayr's user avatar
1 vote
1 answer
193 views

Selecting PFC topology

I'm considering different PFC topologies for the AC-DC stage of a device around 1 kW with aim of optimizing for efficiency and secondarily component size. This far I have identified following options: ...
NoobPointerException's user avatar
0 votes
1 answer
68 views

Output OVP ratings in isolated AC-DC converter

I have an application where there can be considerable inductive flyback current into the supply rail, to raise it above the level naturally outputted by the AC-DC converter (48 V). Namely, the full ...
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