Questions tagged [rectifier]

These are part of AC to DC conversion. A half-wave rectifier keeps only the positive part of the signal. A full-wave rectifier also keeps the negative part, but flips it to make it positive too.

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What are the advantages of full wave bridge rectifier with capacitors parallel to diodes?

I found a circuit where in the classical Graetz rectifier capacitors were added in parallel to each diode. It looked something like this: After the rectifier itself, there was the usual huge ...
AndrejaKo's user avatar
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29 votes
6 answers
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How to convert AC to DC

I am designing a circuit that needs to output 5VDC @ 1A. I'm trying to use a wall transformer to step the voltage down to 12VAC. The next step is the diode bridge and ripple capacitor. The ripple ...
Robert Deml's user avatar
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26 votes
3 answers
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AC to DC without transformer. How does this thing work?

I disassembled a Chinese-made flashlight and found they use just capacitors to bring down the voltage instead of a transformer. They are using it to charge small lead-acid battery. My question is how ...
Ryu_hayabusa's user avatar
22 votes
2 answers
2k views

Half-wave diode rectifier - is textbook wrong?

I've noticed that in all resources on diodes and rectifiers, they show the output voltage as the positive half-wave of the input signal. However, that seems wrong. I understand that there's a voltage ...
MightyPork's user avatar
20 votes
2 answers
3k views

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 ...
Ivan Indir's user avatar
18 votes
5 answers
33k views

Is full wave rectifier better than half wave one?

I am curious if there are practical differences between a DC power supply based on a half wave rectifier or a full wave rectifier. I mean I have a few small DC power supply units which should give ...
Al Kepp's user avatar
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17 votes
3 answers
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Full-bridge converter rectifier kicks

I'm in the process of building an 8kW isolated DC/DC converter, full-bridge topology. I'm seeing some interesting phenomena on the diodes. When each diode becomes reverse-biased, a voltage spike ...
Stephen Collings's user avatar
16 votes
7 answers
10k views

Why are rectifiers-inverters used to drive AC motors instead of using the rectified current to drive DC motors?

I understand the advantages of using a rectifier-inverter system to drive an AC motor instead of simply plugging it into mains power, as it allows much better control of its speed and performance; but ...
Massimo's user avatar
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16 votes
5 answers
64k views

if a standard three-phase 400V AC connection is rectified what DC voltage comes out of it?

If a standard (in Europe and a large part of the world except North America and Japan) three-phase 400V AC (three lines having 230V RMS voltage if measured to neutral each) mains supply is rectified ...
ria's user avatar
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16 votes
6 answers
4k views

Is a half-wave rectifier particularly hard on a transformer?

In the book Practical Electronics for Inventors, 3rd Ed., the authors recommend against using half-wave rectifiers because they're inefficient and cause "...the core to become polarized and to ...
Phil's user avatar
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15 votes
5 answers
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Why don't more devices incorporate full-wave rectifiers as reverse polarity protection?

Recently, I was introduced to the idea of using a full-wave rectifier, in order to protect against reverse polarity damage in DC devices. I hadn't even considered using a rectifier in an already DC ...
Jay Greco's user avatar
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14 votes
3 answers
668 views

Will Stressing a Lamp Filament with AC, DC and/or Relay chatter change its lifespan?

I am building a device that shortens the lifespan of an old style "edison" bulb with an extra long filament as a kind of arbitrary timer. I am planning to "stress" it (not immediately explode it or ...
Oliver Kellow's user avatar
13 votes
6 answers
13k views

How does this rectifier work?

In a car battery charger, I found a strange rectifier. Can someone explain to me how does it work? Here I have a transformer which is unmarked. By measuring resistance between its output terminals, ...
AndrejaKo's user avatar
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13 votes
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Why does this bridge rectifier claim to have no diode forward voltage drop?

I was, "OK, this is feasible," but then I traced how it worked and it simply blocked current through drain and source when a P and N pair are reverse biased. When the other P and N pair are ...
kozner's user avatar
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13 votes
2 answers
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Serial capacitors in electronic ballast of a fluorescent lamp

Recently I repaired one broken electronic ballast of a linear 30W fluorescent lamp. Now it seems to be working as expected, but I had to make some changes to it and I'd like to ask if you see any ...
Al Kepp's user avatar
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12 votes
2 answers
4k views

Reading a Rectifier Diode

How do you read the numbers on a rectifier diode? It only says "06" (or "90") on it (twice, once horizontally and once vertically). I figure I'm supposed to assume this is a 1N4006, but I'm a bit of a ...
manico's user avatar
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11 votes
4 answers
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If multiple sources are parallel with the diode, why does the one with a higher voltage turn on?

I've found this combination in many devices—for example, power supply redundancy modules, Ethernet-powered devices (PD of PoE), and RTC in circuits. In this circuit, the voltage source with a larger ...
Sadat Rafi's user avatar
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11 votes
3 answers
15k views

Bridge rectifier: 4 diodes vs. single chip?

I notice (among the DIY audio enthusiasts at least) that when it comes time to design a power supply for an amplifier, DAC or whatever that the parts list will inevitably include something like "4 x ...
abza's user avatar
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11 votes
4 answers
20k views

Why do we use bridge rectifier?

If we already having a center tap rectifier with just two diodes doing the same work then why is there a need to use four diodes or the so called Bridge rectifier.
user75736's user avatar
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4 answers
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No germanium diode available for small crystal radio -- can active components handle the task?

I know that germanium diodes are trivial to find online, but as this is for a demonstration I'd rather not spend $6-7+ on shipping for a single 5 cent part for a project that's academic in exercise ...
Bryan Boettcher's user avatar
11 votes
3 answers
6k views

Simple \$12V_{AC}\$ to \$12V_{DC}\$ Rectifier

I want to convert a \$12V_{AC}\$ power supply output to use \$12V_{DC}\$ to power some outdoor LEDs. The power supply as it stands will light the LEDs (with a slight flicker from the reverse ...
Matt Wilko's user avatar
10 votes
5 answers
13k views

Full wave rectifier vs full wave bridge rectifier

What is the difference between the full wave rectifier and the full wave bridge rectifier? In other words what do we gain if we use the bridge? As far as I know both do the same thing while the bridge ...
Adam's user avatar
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10 votes
1 answer
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What role does the capacitor and the resistor play in the following circuit?

I opened up an LED light bulb at my home and sketched its circuit diagram as follows: I don't understand what the initial 470n capacitor connected to the live wire and the final 100ohm resistor ...
Kevin Selva Prasanna's user avatar
10 votes
1 answer
6k views

What is the maximum frequency a bridge rectifier can handle?

I was designing a basic power supply with frequency ranging from 50-60Hz and thought about using this bridge rectifier KBPC50005. I cant seem to understand the range of input frequencies it can take, ...
alexhilton's user avatar
10 votes
2 answers
3k views

Isolation Transformer

When a function generator is used to power a full wave rectifier an oscilloscope will not show the correct output due to a shared ground. A half wave is displayed because one of the diodes is 'shorted'...
atomSmasher's user avatar
9 votes
2 answers
2k views

What's the purpose of the full wave diode bridge in this DC-DC power supply?

In the following power supply circuit, there is a full wave diode bridge (full wave rectifier?) after the DC Input. I can see how we need a full wave rectifier after an AC input, but why after a DC ...
Adam Lee's user avatar
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9 votes
5 answers
10k views

What is the purpose of an RC branch accros the diode of a rectifer circuit?

Recently I was going through the data sheet of the TOP264 TOP Switch IC. In a typical application circuit diagram, at the secondary of the transformer they have used a configuration for the diode as ...
noufal's user avatar
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9 votes
6 answers
51k views

How are bridge rectifiers rated?

So I'm getting ready to build a power supply, and it calls for a bridge rectifier. However, I can't find any information about HOW rectifiers are rated, except for a note that (and I don't have it in ...
dwwilson66's user avatar
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9 votes
1 answer
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Bridge rectifier outputting 338 volts DC with 120 volts AC input

I am measuring the live voltages right now and am seeing these numbers. I thought 338 volts DC was the result of rectifying 240 volt AC? I understand that 120 volts AC is the Vrms reading and that ...
56he65h's user avatar
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9 votes
2 answers
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Bridge rectifier in parallel?

Is it possible to safely double the current limit using 4 bridge rectifiers? In one forum I found someone wrote: Use four bridges, one for each leg. Tie the AC input (cathode to anode) ...
JupiterCrash's user avatar
9 votes
2 answers
8k views

LTSpice simulation of rectifier slows down after short time

I have the following simple circuit set up in LTspice: Blue is on the output of the transformer and green from the rectifier. If I don't include a capacitor this works fine and the simulation goes ...
Bitdivision's user avatar
9 votes
1 answer
2k views

Two-sided connectorless USB on a PCB

This question is inspired by Connectorless USB on a PCB. I saw a cool USB LED on AliExpress that can be inserted in either direction: I'd like to build a board with a similar symmetric connectorless ...
sowbug's user avatar
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8 votes
4 answers
2k views

Why does current flow from the most positive to the most negative in three phase system?

I put the following circuit in a simulator to see how it works. I understood it but I have a question: At the time of the vertical green line, The simulator shows me that the current flows from the ...
Michael George's user avatar
8 votes
2 answers
3k views

How to remove huge spikes in current

I am making an DC to AC converter circuit in LTSpice. The schematic is posted below. When I plot the current across the transistors, I get huge spikes in the current, as seen in the diagrams below. ...
Debbie's user avatar
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8 votes
5 answers
22k views

Could most AC devices run off of DC rather than AC?

To be clear - I have absolutely ZERO intention of ever doing this. But when I learned what a rectifier does (flip the negative portion of the voltage into positive), it occurred to me that it ought ...
loneboat's user avatar
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8 votes
2 answers
6k views

Center tap split supply question

Lest's say that I have the following setup: a split supply (using two voltage regulators: a positive and a negative one) connected to a center tapped transformer (12-0-12). The output of the ...
Buzai Andras's user avatar
7 votes
3 answers
8k views

How to determine value of a smoothing capacitor

A friend (who knows even less about electronics than me!) asked me if I could build a circuit that can convert 8 V 50 Hz AC into a DC power supply so he can power a small board that is normally driven ...
Stormcloud's user avatar
7 votes
4 answers
11k views

Schottky barrier diode as a bridge rectifier?

I am building a linear power supply. I need a bridge rectifier and the diodes I currently have can only handle up to a maximum of 1 amp, but I need 4-5 amps. But I have a bunch of YG862C15R Schottky ...
Xane's user avatar
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7 votes
2 answers
38k views

Selecting the right bridge rectifier

There are a number of schematics I'm trying to interpret that have bridge rectifiers. In the components list, however, they're simply listed as "D1-D4 rectifier unit" without any specific values. How ...
dwwilson66's user avatar
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7 votes
5 answers
1k views

Converting 24 VAC to 5 VDC with small output current

I have a transformer which outputs 0.33 A at 24 VAC. I would like to rectify this down to 5 VDC and minimal current, 50 mA being the maximum. I came across the following schematic which seems to be ...
jhorv's user avatar
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7 votes
4 answers
2k views

Mains rectification vs 1:1 transformer

I know you're not supposed to rectify mains because it's "dangerous" but if I use a 1:1 transformer and ground it to earth how exactly am I any "safer"? I ask because it would save me $130 to simply ...
coinmaster's user avatar
7 votes
3 answers
111k views

Full-wave bridge rectifier with capacitor filter and ripple voltage

According to various sources, the ripple voltage of a full-wave bridge rectifier is $$ V_r = \frac{V_s}{2}fCR $$ where \$V_s\$ is the peak of the input voltage source, \$f\$ is the frequency, \$C\$ ...
Douglas Edward's user avatar
7 votes
1 answer
2k views

What is the purpose of parallel RC network in the bridge rectifier output?

Can anybody explain the necessity of the RC network shown in the figure. I found this in circuit for a logic power supply using Fly-Back converter?
noufal's user avatar
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7 votes
1 answer
520 views

How can I rectify up to 85 kV?

I've recently gotten into eletrochemistry, and I found out that if you break through \$\epsilon_{0}\$ with a high enough voltage you can ionize various gasses. I've already wound a 1:1250 EE core that ...
user14828's user avatar
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7 votes
5 answers
21k views

Transformers vs. voltage regulators

I'll start by saying that I'm self-taught in electronics, and tend to ask a lot of questions because I don't know NOT to ask them. This is one of those questions. Consider: I have 120VAC and need ...
dwwilson66's user avatar
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6 votes
3 answers
2k views

Can I use 1000v rectifier diodes instead of 600v rectifier diodes?

I plan on doing some wiring but the directions are asking for 1A 600v rectifier diodes. I could only get my hand on 1000v rectifier diodes and before I continue I want to make sure this is safe as if ...
white_rx's user avatar
6 votes
2 answers
3k views

Why is the efficiency of a half wave rectifier equal to 40.6% and not 50%?

I'm trying to derive the efficiency of a half-wave rectifier using the definition for efficiency, $$\eta = \frac{\text{output power}}{\text{input power}}$$ And I also know that $$P = V_\text{rms} \...
frick's user avatar
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6 votes
3 answers
1k views

Unwanted saw tooth waveform on DC rails

I am somewhat new to electronics and am building up a dual rail power supply. Under no load the DC rails sit at about +15V and -15V. Please refer to the schematic and oscilloscope screenshot (below) ...
Pat's user avatar
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6 votes
2 answers
1k views

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 ...
Divya K.S's user avatar
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6 votes
2 answers
5k views

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 ...
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