All Questions
Tagged with rectifier power-supply
82 questions
0
votes
1
answer
108
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Would an AC EMI filter capacitors contribute to inrush current?
Shown below is an EMI filter for an AC input. My doubt is when I analyse the inrush current, should I be considering the contribution due to all three capacitors?
a) Differential mode capacitors
b) ...
- 3,156
2
votes
2
answers
249
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Exploding/superhot capacitor in XT AC-DC PSU
I have a commercial replacement PSU that I am using for a vintage XT class computer which has 4 DC lines (5v, 12v, -12v and -5v). On fitting the PSU however, the PC operated but after a while under ...
- 23
1
vote
1
answer
101
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Valve amp power supply filtering with centre tapped transformers
I am designing a valve amplifier and am planning to use GU50 output pentodes in the power stage (PP). They can take up to 1kV on the anode but have an upper limit of 250V on the screen (which also ...
0
votes
2
answers
286
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Peak to peak voltage
What is the formula to calculate the peak to peak voltage at the input of 7805 voltage regulator/at the output of 10 microfarad capacitor in this circuit?
https://theorycircuit.com/7805-ic-circuit-...
- 1,586
1
vote
2
answers
148
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Identifying faulty component in AC-DC regulated PSU
I'm debugging this faulty AC-DC power supply circuit, which is meant to output 24 V DC from a 240 V AC supply. The 24 V line is actually about 10.1 V under load.
I have tested ZD1 and ZD2 which seem ...
- 13
0
votes
2
answers
89
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AC to DC supplier values not even
I've been trying to make a dual power supply from AC signal to power some op-amps, but the value I'm getting is very far from even. I'm getting +15.5V from the positive pin of the rectifier and -7.7V ...
- 1,187
0
votes
1
answer
61
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Are DC microgrids more efficient? Calculating peak and RMS current in DC rectifiers
I'm calculating the energy losses of using AC to power rectified (DC) devices.
Rectified loads have capacitor filters that demand sharp peaks of current. This increases conduction losses across the ...
user332999
2
votes
1
answer
595
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Using body diodes of MOSFET for power rectification
I am designing a switch-mode welding power supply. The secondary current is 130 A at 24 V max and the switching frequency is 20 kHz. Using Schottky diodes for full bridge rectification results in ...
- 65
0
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0
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47
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Voltage drop in synchronous rectifier for post regulation of low voltage rail in multi-output PS?
Consider a supply for 3.3 V (V1) and 24 V (V2), 96 W each.
I'd expect synchronous rectification with V1, and post regulation with V2.
To decrease the Volt-seconds for an inductor, it seems ...
- 2,056
0
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1
answer
54
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Do you think the output voltage is caused by an old capacitor?
I have a vacuum tube power supply which isn't producing the correct output voltage. I have removed the tube and all that is left is the transformer, inline 22 ohm resistor, CR201/202, R202/203 and ...
- 95
1
vote
1
answer
100
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LDO powered by a half-bridge rectifier connected to 9 VAC ripples when under load
I've been working on the a breakout board or the Pi Pico to measure voltage and current as well as turn on and off two relays.
I've been basing it off of OpenEnergyMonitor's emontx3 and they suggested ...
1
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3
answers
76
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Rectifier circuit behavior - Need an intuitive understanding
Case1: OUT Series res = 10 ohm -> spiky input current reaching upto 15 A -> capacitor charging fast
After a long time:
Case 2: OUT series res = 100 ohm -> almost sinusoidal input current ...
- 3,156
-2
votes
2
answers
130
views
What is this component in a power supply?
We bought a Cisco 6500 series 6 kW PSU and took it apart. This is a module connected immediately to the inputs of the power supply unit. Does anyone know what it does?
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3
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335
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What are the assumptions involved in below rectifier output waveform?
The below waveform shows peak current occurs at the instant when diode starts conduction. Why is the peak current not happening at the max input voltage point?
Usually the rectifier output caps are ...
- 3,156
6
votes
2
answers
1k
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Why is the telecom input power supply range 36 to 72 V (polarity ignored)?
Why is the telecom power supply voltage level specifieded with a wide range: 36 to 72 V?
Is it because the rectified AC voltage would have variations as per AC line variations? We could easily get a ...
- 3,156
0
votes
2
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338
views
Which replacement standard recovery diodes do I use for a high voltage full bridge rectifier in a valve guitar amplifier?
The original diodes were four IN4007 (1A 1000V PRRV.)
If I replace them with IN5408RGL (STANDARD DIODE, 3A, 1KV PRRV,) basically upping the current to 3A, will this have any detrimental effect on the ...
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3
votes
3
answers
305
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Not able to figure out the logic behind sense circuitry of a AC/DC converter
In the below circuit, why would there be 2 extra diodes (D3 and D4) to sense AC input voltage?
If D3 and D4 act as rectifier, wouldn't it be sufficient to directly sense at the output of bridge ...
- 3,156
0
votes
3
answers
3k
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Transformer - 2 Wires in and 3 wires out - How to connect ground?
I have the following transformer:
And the following power cable:
This is for a dual-polarity power supply for some audio circuits. How should I connect the ground pin to this circuit? Can the ...
- 45
5
votes
3
answers
1k
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The use of capacitors in voltage regulator schematic using 7805 and 7812?
I'm a newbie in electronics so I lack a lot of basic electronic knowledge.
I found this schematic about making regulated power supply 5 V and 12 V DC from AC. The diagram is below:
This is what I ...
- 53
1
vote
3
answers
244
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Why is a secondary transformer winding for VT filament heater connected to rectified output? [duplicate]
Ok I know this is a pretty narrow question. I'm learning about vaccum tubes, and I think I have the basics down, but this particular setup is confusing me. See the attached picture.
In the given ...
- 13
1
vote
1
answer
757
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In Chinese Led torch how does the LED automatically light down when recharging? [closed]
I repaired some led rechargeable torches which work under 230 V.
When we plug it to main socket for charging even with the switch on, the LED goes off. What mechanism in these torches to off the LED ...
- 114
3
votes
0
answers
410
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What could be burning the schottky diode in this synchronous rectifier?
I have this TV PSU which has one supply circuit for the TV motherboard, which it calls "standby" in the scheme (AO3).
Here's a portion of the AO3 circuit where most of the components I'll ...
- 771
0
votes
4
answers
2k
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Should I buy a diode with higher maximum ratings if it costs the same?
I need a diode that prevents surge currents from a DC motor flowing back into the power supply.
The motor draws a continuous of 10A at 12V.
Was checking a store for a rectifier diode and found out, ...
- 195
1
vote
1
answer
919
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Can I use rectifier diodes with DC (1N4002)?
I have an HTronic 19 00 33 AC/DC converter. I would like to use it as a DC/DC step down converter to transform 12V DC into 5V.
I could not find the datasheet in English, here is the German version.
...
- 1,256
1
vote
2
answers
95
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Analogue current and voltage regulation and rectification thereafter
I am a research scholar working on mechanical metallurgy as a part of my engineering study.
For my project (a new kind of electroplating,) I need voltage ranging from minimum 0V to maximum 170V DC. We ...
1
vote
1
answer
364
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 ...
0
votes
0
answers
310
views
Uneven current distribution in center-tap transformer secondary winding of LLC resonant converter at low load
I'm trying to design an 24V 50W LLC resonant converter with a resonance frequency of 250kHz.
I've run into an issue with the center-tapped transformer that i can't quite find a reason for though.
For ...
0
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3
answers
259
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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 ...
20
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2
answers
3k
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Power supply - purpose of the capacitor on the side of the transformer before full bridge rectifier
I was wondering if someone can explain the purpose of the capacitor C1141 from the attached picture. I know that C1142 is a filter cap: that much is obvious to me. However, I can't seem to grasp the ...
- 301
1
vote
0
answers
101
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Why are many 9V DC wall adapter power supply measured as 12-14V by a multimeter? [duplicate]
I have tried with many (working) 230V - 9V DC wall adapter power supply (of different brands, some of them coming with an electronic Yamaha device, etc.):
they all show a higher voltage when ...
- 2,198
-2
votes
2
answers
648
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Alternative to center tapped transformer [closed]
I would like to replace a center tapped transformer, which is directly connected to a full bridge rectifier, by two DC lab power supplies.
Does that make sense at all?
The power connector goes ...
- 1,086
3
votes
1
answer
113
views
Rectifying reversible polarity battery with minimal power loss
I'd like to build a battery-powered DC power supply that will accept a single-cell battery in either polarity (i.e. it doesn't matter which way you put the battery in). I'm thinking of using the ...
- 275
0
votes
0
answers
42
views
Simplest and chepest way to provide 3.3V@150mA from power supply running at 6Vrms@120mW
I have a power supply that can provide 6Vrms (50kHz) and 130mW max (maybe a bit more). Unfortunately, for my project I need a peak of 150mA in 3.3Vdc (ESP8266) in regular basis during TX but most of ...
- 101
0
votes
0
answers
63
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Rectified X2 circuit gives 2 voltages depending on how the powerplug is connected to the wall (EU)
simulate this circuit – Schematic created using CircuitLab
I'm trying to control a mosfet directly from a phase shifted 50Hz sine wave. But when I was trying to understand the voltage drop with ...
- 101
0
votes
2
answers
275
views
2
votes
1
answer
103
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Resistor network in half bridge rectifier
I have come across the following half bridge rectifier circuit connected across phase R and T.
I'm wondering about the large resistor network in parallel with the source. What is the point of this ...
- 313
0
votes
2
answers
318
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Low cost power supply redundancy
I'm looking at coupling the output of two computer PSUs, driving a fairly stable high power project (around 300-400W peak) most likely using all output rails (12V, 5V, 3.3V) all well within the rated ...
- 143
1
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2
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365
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Why does current associated with a rectifier said to have both ac and dc components?
Why does current associated with a rectifier said to have both ac and dc components. Also how are they combined?
0
votes
1
answer
75
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Current limiting resistors for preventing shorts at power supply turn-on [duplicate]
In a text it mentions about a power supply that the filter cap will act as a short at initial turn-on. Below I showed these points as A and B:
In this case, the diode will have a surge current Is. ...
- 1,905
1
vote
1
answer
4k
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Overheating Diode
The mains supplies 240VAC, the transformer is rated at 240V/12-0-12V (Center tap), 3A. The load is made up of a single 12V 36 Watts PTC heater. The diode is T6A10 (Max forward current is 6A), The ...
4
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2
answers
701
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Need help identifying a mystery component with double-diode marking
I've found this MOSFET-shaped component inside a Dell laptop power supply (I've lost the case so I can't tell you any details, sorry):
The problem is that I can't find any datasheet for it anywhere.
...
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0
votes
1
answer
74
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What factor limits power supply output power?
Why is it many DC power supplies (for simpler systems that don't need amazingly clean power, for example) have a very low rates output power, e.g 12V 1A?
What makes a supply consisting of a 20:1 turn ...
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3
votes
2
answers
7k
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Calculation of ripple voltage after rectifier (equation from TAOE)
I am reading The Art of Electronics, Third Edition by Paul Horowitz and Winfield Hill but I feel like I am missing something when the book comes to talk about (begins to, instead) Power-supply ...
- 866
3
votes
3
answers
564
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Purpose of series resistors in this bipolar rectifier circuit?
The following circuit uses two series resistors, one for each polarity of the supply. I understand function of smoothing caps and overvoltage zener diodes, but the resistors I do not. I would like to ...
- 161
1
vote
3
answers
18k
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How to calculate ripple voltage in this bridge-rectified zener-regulated circuit?
For one of my labs I need to design a power supply with the ripple less than 1% of the nominal 4.7 V value (since Vz = 4.7 V) and calculate its load regulation.
I know that the ripple will most ...
- 127
4
votes
4
answers
7k
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Why sine wave not square wave?
Rectifying square wave voltage seems to give us DC directly without the need of a capacitor. so, why do we prefer sine wave over it?
What would change if I powered any adapter (laptop adapter as ...
- 1,511
2
votes
3
answers
2k
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Location of diode bridge on transformer circuit?
I'm designing a full bridge rectifier that takes 110vAC to 4-16vDC for input into a 5v switching regulator.
I opened a few 5v power supplies and they place the bridge on the high voltage side. Why ...
- 463
-4
votes
1
answer
687
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Questions about a basic power supply
What is the difference between the peak voltage and the rms voltage? In our country, the standard voltage in houses is 220V AC. Is it peak or rms?
In the rectifier (I use full-wave bridge rectifier), ...
- 19
6
votes
2
answers
5k
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How can I observe rectifier switching noise?
I understand there is such a thing as rectifier switching noise. I would like to observe it on the bench, but I don't understand its causes well enough to design a test setup.
Once in hand, I'd like ...
- 7,152
4
votes
4
answers
4k
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Is a linear voltage regulator necessary in AC to DC?
I was doing research on AC to DC power supplies and I came across a lot of schematics that use regulators like the one below:
credit: http://www.instructables.com/id/Make-a-simple-12-volt-power-...
- 803