Talk:Rectifier
From Wikipedia, the free encyclopedia
In an alternator with an eight-diode rectifying unit, what are the last two diodes for? I can't find any information on this.
Images are slightly too big. I increase the text font and that shoves the image to right.
a rectifier is a circuit which converts bidirectional current(ac) to unidirectional(dc). earlier rectifier was a single diodeconnected to the output of a transformer.but there was some ac still present in the output which is measured by a factor called ripple factor.therefore a low ripple is desired in output of rectifier the above arrangement is known as half wave rectifier, then to remove the ac a full wave rectifier was used this arrangement was of two diodes.
This page should discuss the older technologies that have been used for high-capacity DC power systems, such as motor-generator sets and mercury arc rectifiers. -- Anonymous, 05:25 June 11 (UTC)
Have been trying to find out what a half-wave rectifier is, and there's nothing on the page itself about this.
This page should also discuss controlled rectifiers
Contents |
[edit] more stuff
whats the ripple frequency for a half wave rectifier plugged into a line voltage?
does the filte rcapacitor act as a low pass or high pass filter?
does the filter capacitor reduce ripple voltage or ripple frequency?
if a diode fails in a ful wave, what happens to ripple voltage and frequency?
IF THESE INCREASE THIS WILL MAKE RIPPLE VOLTAGE
resistance load current
if a filter capacitor opens, ripple voltage equals? what if it shorts?
just some interesting questions you may want to include in the article!
[edit] "Rectifier efficiency"
The eight / pi^2 figure does not refer to the ratio of output power to input power; it only refers to vdc^2/vac^2. The two are not at all the same. 19% of the input power is not dissipated by the rectifier under ideal conditions. That part needs to be rewritten.
- Remember the rectifier effiency is the power of the output DC component over the AC input power. Not the total output power over total input power (which would be 100% for an ideal fullwave rectifier).
-
- A quick google search for "rectifier efficiency" does not show this to be a common definition for those words. I can't imagine why it would be; why would that number (average Vout divided by peak Vin, all squared) ever be meaningful? I have therefore removed the definition, and the rest of the section was more or less completely incoherent, so I removed that as well.
I have no idea, either, where it came from. However, if you look at the math (integrate), the ratio of peak DC voltage to mean DC voltage (not RMS, but true mean) for a rectified wave, is VpeakDC/VmeanDC = pi/2. So your voltage when you filter it, will actually increase by that much. And power by the square of that. But these give "efficiencies" of greater than 1, basically because the smoothed DC output is at AC peak voltage, not AC (RMS). If the AC(peak) is AC(RMS)*SQRT2 and we forget diode drop and set AC(peak) = DC(peak), then the ratio of AC(RMS) to DC(mean) voltage is:
VAC(RMS)/VDC(mean) = [V(peakDC)/(SQRT2)]/V(meanDC) = pi/(2SQRT2) = 1.11
The inverse of this is about 90%.
So I don't know where this figure used comes from. The only thing that gives 4/pi^2 is the square of VDC(mean)/VDC(peak), or VDC(mean)/VAC(peak). But I can't see the physical meaning of either ratio. SBHarris 03:05, 20 August 2006 (UTC)
[edit] Music
I first encountered rectification when researching how to build myself a guitar effects pedal. The output frequency of a full rectifier is effectively double the input frequency, and is therefore convenient in producing an "octave" effect.
This is really about the extent of what I know about the topic, and if someone more knowledgeable could insert it into the article in a better articulated fashion, I think it would be a good addition. If you think I articulated the idea well enough, feel free to just cut and paste it into the article. Shaggorama 00:04, 6 March 2006 (UTC)
[edit] Change article title
I suggest a change of title. This article is called rectifier (after the device) then goes on to talk mostly about rectification (the process). I suggest that
- This rectifer article be renamed to rectification.
- rectifier be redirected to diode
John Dalton 21:10, 15 March 2006 (UTC)
- I would go along with the rectification change, although when done you know somebody's just going to carp that the article goes on to talk about various kinds of rectifiers, and should be called THAT. You want verb or noun?
I object to the change to diode because many of the old high-power systems (before the fancy silicon high power diodes) like arc rectifiers and AC-powered DC-generators, were certainly not diodes in the sense that we know them. They need to be added into the article as has been noted, but nobody has gotten around to it yet. Eventually. SBHarris 09:07, 4 September 2006 (UTC)
[edit] Peak loss
Maybe it should be pointed out that the peak loss for full wave rectification is 2 times 0.7, as two diodes are involved? Done that - JJ
[edit] anyone fancy
drawing the input/output graphs for the 3 phase bridge? ;) Plugwash 22:32, 3 September 2006 (UTC)
Notice the diagram for the full rectification. Shouldn't there be a flat portion between each hump? Until each diodes passes its specified voltage (~.6-.7V for Si diodes) then there will be no current across the load?
- Yes, real diodes will introduce a small flat portion, i wonder though if introducing this into the diagrams will confuse more than it will help though. Plugwash 18:02, 23 October 2006 (UTC)
[edit] Rectifier Relationships
I'm doing my lab report on rectifier circuits and I really need rectifier relationships both Vdc and Vrms values produced by all types of rectifiers. Well current might be added as well. I have some, might add them, when I finish, cause it is due soon. Can anyone please add them? —The preceding unsigned comment was added by Dmitrij.ledkov (talk • contribs) 21:51, 12 February 2007 (UTC).
- The relatonships depend on the design of the rectifier, the properties of the components, and the load. We might be able to provide approximate relationships; how accurate do the relationships need to be? --Gerry Ashton 22:44, 12 February 2007 (UTC)
[edit] "Rectifier Diode" image
This is not a diode this is an SCR (notice the gate connection). —The preceding unsigned comment was added by 203.166.229.52 (talk) 14:36, 19 February 2007 (UTC).
[edit] 3-phase rectifier
Is there a significance in which order the 3 live wires are fed into it, or can the connection be arbitrary? --194.251.240.114 23:45, 27 March 2007 (UTC)
- The answer to that question should be obvious from the schematic. Plugwash 20:53, 30 March 2007 (UTC)
