Rectifier Types? - Page 1
Forum section: electronics / beginners

author: Undweeber
author_rank: Regular Contributor
timestamp: April 04, 2018, 12:22:19 am
content: What is the difference betweenrectifierandfull bridge rectifierwhen i googled full bridge rectifier it had capacitors and such

author: Whales
author_rank: Super Contributor
timestamp: April 04, 2018, 12:31:32 am
content: The capacitors are almost always used along with a rectifier, but are not part of the rectifier itself.Rectifier is a generic term. "half wave rectifier" and "full bridge rectifier" are two common designs.https://en.wikipedia.org/wiki/RectifierThere's also more advanced/complicated forms of rectifiers that use active components to reduce power wastage, but these are pretty rare except in very high efficiency devices (eg expensive PSUs).

author: Undweeber
author_rank: Regular Contributor
timestamp: April 04, 2018, 12:33:54 am
content: I made a basic rectifier out of diodes, what type of rectifier is that?I also scavenged a rectifier chip which is like one inch square flat thing a PC power supply, what type of rectifier is that?

author: firehopper
author_rank: Frequent Contributor
timestamp: April 04, 2018, 12:44:00 am
content: the one you made depends on how many diodes and how they are connected, the other thing is more than likely a full bridge rectifier.

author: David Hess
author_rank: Super Contributor
timestamp: April 04, 2018, 02:32:18 am
content: A bridge rectifier has four rectifier diodes in a bridge configuration. There is nothing wrong with using four separate rectifiers or two dual rectifiers wired as a bridge.Note that while a bridge rectifier operates as a full wave rectifier, so can two diodes or a dual rectifier with a center tapped transformer which may be preferable in some applications because the voltage drop will be halved.

author: Undweeber
author_rank: Regular Contributor
timestamp: April 04, 2018, 03:51:00 am
content: i am pretty sure i made a full bridge rectifier using 4 diodes

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 04, 2018, 04:22:27 am
content: It may help your understanding to realize that half wave and full wave are descriptions of how much of the AC signal is used in the output, while bridge is a circuit arrangement. So when you say full wave bridge you are actually saying two different things about the same circuit.Half wave means that only one half of the incoming ac signal is transmitted to the output. It may be the positive half or the negative half depending on how you arrange and use the circuit. Full wave means all of the ac signal is used. Since if you just took the positive half and negative half and added them you would end up with nothing there has to be some form of switching or guidance to get the full effect. The bridge configuration of four diodes is one of the most common methods.

author: oldway
author_rank: Super Contributor
timestamp: April 04, 2018, 08:52:08 am
content: I thing the name FULL bridge rectifier is only used when you use SCR's....a full bridge rectifier is a bridge with only SCR's and not a mix of diodes and SCR's.For a bridge rectifier with only diodes, no need to name it FULL bridge rectifier.

author: Brumby
author_rank: Unknown
timestamp: April 04, 2018, 09:10:56 am
content: Quote from: oldway on April 04, 2018, 08:52:08 amI have never come across such a distinction - but then there's a lot I don't know.

author: ovnr
author_rank: Frequent Contributor
timestamp: April 04, 2018, 09:33:10 am
content: Quote from: oldway on April 04, 2018, 08:52:08 am"Full bridge rectifier" is short for "Full wave bridge rectifier". It applies to any rectifier that utilizes the full wave. It doesn't matter if it's diodes, SCRs, or actively driven transistors.

author: tautech
author_rank: Super Contributor
timestamp: April 04, 2018, 09:42:28 am
content: Quote from: Undweeber on April 04, 2018, 12:22:19 amApplication.Quote from: Undweeber on April 04, 2018, 12:33:54 am4 diodes = bridgeQuoteBridge again.Study the link that Whales offered as it shows most applications of diode usage for rectification.

author: oldway
author_rank: Super Contributor
timestamp: April 04, 2018, 10:09:40 am
content: Quote from: ovnr on April 04, 2018, 09:33:10 amIt seems to me that a bridge rectifier is always a full wave rectifier even if it is used with center tap transformer ....Center tap rectifier with 2 diodes is also a full wave rectifier but it is not a bridge rectifier.

author: Undweeber
author_rank: Regular Contributor
timestamp: April 05, 2018, 03:25:47 am
content: Okay so the exact 2 rectifier chips that I have are as follows:GBJ2J- 2.0A GLASS PASSIVATED SINGLE-PHASE BRIDGE RECTIFIERhttp://pdf1.alldatasheet.com/datasheet-pdf/view/184803/WTE/GBJ2J.htmlGBU8K- RECTIFIER BRIDGE 8A 800V GBUhttps://www.digikey.com/product-detail/en/vishay-semiconductor-diodes-division/GBU8K-E3-45/GBU8K-E3-45GI-ND/604838so are these full wave rectifiers? will they be able to turn 21 VAC to DC? what is the lowest voltage they can operate at? would they work well at hand crank speeds or should i rather use 4 diode bridge rectifier? would this type even convert full wave of AC to DC or does it only use half a wave? do the ones i have utilize full wave?

author: tautech
author_rank: Super Contributor
timestamp: April 05, 2018, 03:55:11 am
content: Quote from: Undweeber on April 05, 2018, 03:25:47 amOther than their individual specs, they are both rectifier bridges.They convert AC to full rectified DC......not pure DC as to get that you must add smoothing caps.

author: Brumby
author_rank: Unknown
timestamp: April 05, 2018, 05:01:30 am
content: Quote from: ovnr on April 04, 2018, 09:33:10 amOK. That makes sense - but it's not something I've encountered before.Quote from: oldway on April 04, 2018, 10:09:40 amYep.

author: Zero999
author_rank: Super Contributor
timestamp: April 05, 2018, 10:01:09 am
content: Quote from: oldway on April 04, 2018, 10:09:40 amVery true. A full wave rectifier only needs two diodes and a transformer, to generated split phase AC. This design was very common, when diodes were expensive.Now cheap silicon and Schottky diodes are widely available, a four diode bridge rectifier is more common.http://learning.uonbi.ac.ke/courses/SPH307/scormPackages/path_2/43_the_fullwave_rectifier1.html

author: Cliff Matthews
author_rank: Unknown
timestamp: April 05, 2018, 11:52:31 am
content: On dual rectifiers with CT transformers:How does one calculate I-max DC after decent smoothing caps?(sinceonly half of secondary winding conducts on each half-cycle, can useful current yield be increased as a general rule?)Eg: I have not tested this, but I have25.2vct @ 2amps. Is end result ~17vdc @ 3amps?(counting single diode drop)(** This assumption draws 50% more current out of each half winding based on available flux in the core)

author: David Hess
author_rank: Super Contributor
timestamp: April 05, 2018, 12:40:37 pm
content: Quote from: oldway on April 04, 2018, 10:09:40 amIt becomes two center tapped full wave rectifiers.

author: Cliff Matthews
author_rank: Unknown
timestamp: April 06, 2018, 01:17:44 am
content: Quote from: Cliff Matthews on April 05, 2018, 11:52:31 am@Undweeber, sorry if that stretched the purpose of your thread..**edit:Still it's useful to knowif the full-wave, dual-rectifier circuit makes reason to up-rate a transformers output on a single-rail supply. (withinreasonable limitsof secondary winding ampacity)

author: james_s
author_rank: Super Contributor
timestamp: April 06, 2018, 04:03:13 am
content: Quote from: Undweeber on April 05, 2018, 03:25:47 amThe bottom end of the voltage range is limited by the forward drop of the diodes, the 800V rectifier could have around a 2V drop when you factor in that two diodes will be conducting at a time. Whether you use an integrated bridge or separate diodes makes no difference at all, those bridge rectifier modules contain four diodes inside. If you need a very low voltage drop you could use Schottky diodes.