Author Topic: Load between battery and capacitor  (Read 4717 times)

0 Members and 1 Guest are viewing this topic.

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #25 on: November 23, 2021, 07:23:43 pm »
I mean this...


 

Offline fourfathom

  • Super Contributor
  • ***
  • Posts: 1849
  • Country: us
Re: Load between battery and capacitor
« Reply #26 on: November 23, 2021, 07:31:42 pm »
I mean this...



I don't see how, the diodes in series with the capacitor will block any discharge current.  And those two "2nd rail member" diodes are shorting out the two rails (with a 2-diode voltage drop), so the capacitor actually has about zero volts across it anyway.  Let's just say I'm confused by your example.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 
The following users thanked this post: tooki

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #27 on: November 23, 2021, 07:36:20 pm »
Just imagine a bit of equal resistance there,  and it works fine.

Yes, the diodes dont block the discharge current,  thats what I meant,     If you were putting diodes there to block the discharge current it doesnt work, because the current is going two ways through the diode at the same time.
« Last Edit: November 23, 2021, 07:43:22 pm by Capernicus »
 

Offline Manul

  • Super Contributor
  • ***
  • Posts: 1105
  • Country: lt
Re: Load between battery and capacitor
« Reply #28 on: November 23, 2021, 07:45:09 pm »
Its not supposed to be a bridge rectifier,   but its demonstrating a point that if a diode is forward biased,  then it is open to conduct in both directions, not just forwards.   if its reverse biased, it wont conduct in either direction.

So what I'm meaning is to do with ac->dc conversion -> The "smoothing" capacitor might conduct backwards, if the ac power source has opened for conduction the diode for it.

Actually Capernicus is quite correct here. When diode is forward biased and it is on, it can conduct both directions in a sense, that it remains on for some time after reverse bias voltage is aplied. Practical diode is not ideal, it has forward drop, reverse recovery time, reverse breakdown voltage, capacitance and some other things which we usually don't want, but it's there. Sadly, other statements are seriously messed up.
 

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #29 on: November 23, 2021, 07:49:28 pm »
Its not supposed to be a bridge rectifier,   but its demonstrating a point that if a diode is forward biased,  then it is open to conduct in both directions, not just forwards.   if its reverse biased, it wont conduct in either direction.

So what I'm meaning is to do with ac->dc conversion -> The "smoothing" capacitor might conduct backwards, if the ac power source has opened for conduction the diode for it.

Actually Capernicus is quite correct here. When diode is forward biased and it is on, it can conduct both directions in a sense, that it remains on for some time after reverse bias voltage is aplied. Practical diode is not ideal, it has forward drop, reverse recovery time, reverse breakdown voltage, capacitance and some other things which we usually don't want, but it's there. Sadly, other statements are seriously messed up.

From what I looked at it.  (That the other poster was kind enough to set up a simulation of,  thankyou.) In an ideal sense it looks like the diode behind is left uncharged by the battery when the front diode is charged,  so the back diode actually stops this phenomenon I'm talking about in the happenstance of the ac->dc converter.

So that gives me an idea.  if you use a diode bridge, you can actually separate your rail with it - and it stops cap discharge? :)
« Last Edit: November 23, 2021, 08:10:35 pm by Capernicus »
 

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #30 on: November 23, 2021, 08:21:56 pm »
 

Offline Gyro

  • Super Contributor
  • ***
  • Posts: 9410
  • Country: gb
Re: Load between battery and capacitor
« Reply #31 on: November 23, 2021, 08:43:02 pm »
Can you please stop posting facebook links, they will become orphaned and useless. If you have images to attach then please attach them to your posts.
Best Regards, Chris
 
The following users thanked this post: Capernicus

Offline ogden

  • Super Contributor
  • ***
  • Posts: 3731
  • Country: lv
Re: Load between battery and capacitor
« Reply #32 on: November 23, 2021, 08:55:36 pm »
I mean this...



I don't see how, the diodes in series with the capacitor will block any discharge current.  And those two "2nd rail member" diodes are shorting out the two rails (with a 2-diode voltage drop), so the capacitor actually has about zero volts across it anyway.  Let's just say I'm confused by your example.

Right. Electricity and Electronics does not work according to beliefs. You want to know something first before you give lessons to anybody.
 
The following users thanked this post: Capernicus

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #33 on: November 23, 2021, 09:07:21 pm »
One day I'll go and proove this one with prototypin',   but I'm always so tired and have plenty of other things to do than continue on with my electronics theory atm.

I'm doing programming, mech logic + ceramics, other than this, so I can only do one thing at a time.  I'm just about ready to drop unconscious I'm so busy.    :=\
 

Offline SL4P

  • Super Contributor
  • ***
  • Posts: 2318
  • Country: au
  • There's more value if you figure it out yourself!
Re: Load between battery and capacitor
« Reply #34 on: November 23, 2021, 09:10:37 pm »
I’d love to see some of the software you’ve created.
Don't ask a question if you aren't willing to listen to the answer.
 
The following users thanked this post: Capernicus

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #35 on: November 23, 2021, 10:00:19 pm »
I haven't got much programming done in a while either,  But I did this inverse kinematics for this here little 4 legged spider. :)



And a really wierd one,   its cranks connecting to cranks to cranks, for a step up transmission,  I've actually improved this design now so It can reverse cycle direction and step down as well as step up.



Note I had to compute inverse kinematics all the way down the chain to get that,   I'm still yet to print it out to see if it works.



Thats programming inside the OPEN-SCAD language, for CAD.   But I actually coded OPEN-SCAD in visual studio before I found it existed already,   Heres the video to proove it->

« Last Edit: November 23, 2021, 10:06:07 pm by Capernicus »
 

Offline fourfathom

  • Super Contributor
  • ***
  • Posts: 1849
  • Country: us
Re: Load between battery and capacitor
« Reply #36 on: November 23, 2021, 11:20:52 pm »
Its not supposed to be a bridge rectifier,   but its demonstrating a point that if a diode is forward biased,  then it is open to conduct in both directions, not just forwards.   if its reverse biased, it wont conduct in either direction.

So what I'm meaning is to do with ac->dc conversion -> The "smoothing" capacitor might conduct backwards, if the ac power source has opened for conduction the diode for it.

Actually Capernicus is quite correct here. When diode is forward biased and it is on, it can conduct both directions in a sense, that it remains on for some time after reverse bias voltage is aplied. Practical diode is not ideal, it has forward drop, reverse recovery time, reverse breakdown voltage, capacitance and some other things which we usually don't want, but it's there. Sadly, other statements are seriously messed up.

Sure, reverse recovery time, minority carrier lifetime, etc.  But these are transient effects and not what I believe Capernicus is talking about, and certainly not effects that will discharge a bulk "smoothing" capacitor.  If he is, I wish he would clarify.  Sorry, this is making less and less sense.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #37 on: November 24, 2021, 12:04:29 am »
Its not supposed to be a bridge rectifier,   but its demonstrating a point that if a diode is forward biased,  then it is open to conduct in both directions, not just forwards.   if its reverse biased, it wont conduct in either direction.

So what I'm meaning is to do with ac->dc conversion -> The "smoothing" capacitor might conduct backwards, if the ac power source has opened for conduction the diode for it.

Actually Capernicus is quite correct here. When diode is forward biased and it is on, it can conduct both directions in a sense, that it remains on for some time after reverse bias voltage is aplied. Practical diode is not ideal, it has forward drop, reverse recovery time, reverse breakdown voltage, capacitance and some other things which we usually don't want, but it's there. Sadly, other statements are seriously messed up.

Sure, reverse recovery time, minority carrier lifetime, etc.  But these are transient effects and not what I believe Capernicus is talking about, and certainly not effects that will discharge a bulk "smoothing" capacitor.  If he is, I wish he would clarify.  Sorry, this is making less and less sense.

Yes I dont mean that.   I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes,  but it turns out another one of the diodes stops the cap discharge separately.
 

Offline fourfathom

  • Super Contributor
  • ***
  • Posts: 1849
  • Country: us
Re: Load between battery and capacitor
« Reply #38 on: November 24, 2021, 05:08:24 am »
I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes

I think this "activating the diodes" is the root of the misunderstanding.  As long as we aren't considering leakage, capacitance, or minority carrier lifetime, current will not flow "backwards" through a diode regardless of its previous state.  However, I think you still believe otherwise.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 
The following users thanked this post: Capernicus

Online Zero999

  • Super Contributor
  • ***
  • Posts: 19344
  • Country: gb
  • 0999
Re: Load between battery and capacitor
« Reply #39 on: November 24, 2021, 08:29:13 am »
One day I'll go and proove this one with prototypin',   but I'm always so tired and have plenty of other things to do than continue on with my electronics theory atm.
You seem to have plenty of time to argue the toss. It would be better spend it prototyping, before asking questions.
« Last Edit: November 24, 2021, 10:19:34 am by Zero999 »
 
The following users thanked this post: george.b, Capernicus

Offline ogden

  • Super Contributor
  • ***
  • Posts: 3731
  • Country: lv
Re: Load between battery and capacitor
« Reply #40 on: November 25, 2021, 09:15:31 pm »
I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes,  but it turns out another one of the diodes stops the cap discharge separately.
If you got diode property wrong then clearly you would want to learn ALOT before even trying to spread your (clueless) wisdom in "I know it all" style.

[edit] Oh, and I am not even talking about ridiculous circuit with two series diode short in it...
« Last Edit: November 25, 2021, 09:20:29 pm by ogden »
 
The following users thanked this post: tooki

Offline Capernicus

  • Frequent Contributor
  • **
  • !
  • Posts: 483
  • Country: au
Re: Load between battery and capacitor
« Reply #41 on: November 26, 2021, 12:31:03 pm »
I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes,  but it turns out another one of the diodes stops the cap discharge separately.
If you got diode property wrong then clearly you would want to learn ALOT before even trying to spread your (clueless) wisdom in "I know it all" style.

[edit] Oh, and I am not even talking about ridiculous circuit with two series diode short in it...

My model of electricity is incomplete and approximate,   if yours is too I wont attack in the forumm of saying that it doesnt work most the time anyway,   everyone has their little guesses of whats going on,  sometimes it works out, sometimes it doesnt,  the ending details of what actually happens I think 99% of ppl get it wrong (so u have to do experiments to proove ideas.),  so I dont get anything perfect myself either, and I think that's all you need to get your machines up and running, being perfect would be good but its not the end of the world if you get things wrong, as long as u test all your ideas just to make sure of the missing details.
 

Offline tooki

  • Super Contributor
  • ***
  • Posts: 11332
  • Country: ch
Re: Load between battery and capacitor
« Reply #42 on: November 26, 2021, 12:50:28 pm »
I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes,  but it turns out another one of the diodes stops the cap discharge separately.
If you got diode property wrong then clearly you would want to learn ALOT before even trying to spread your (clueless) wisdom in "I know it all" style.

[edit] Oh, and I am not even talking about ridiculous circuit with two series diode short in it...

My model of electricity is incomplete and approximate,   if yours is too I wont attack in the forumm of saying that it doesnt work most the time anyway,   everyone has their little guesses of whats going on,  sometimes it works out, sometimes it doesnt,  the ending details of what actually happens I think 99% of ppl get it wrong (so u have to do experiments to proove ideas.),  so I dont get anything perfect myself either, and I think that's all you need to get your machines up and running, being perfect would be good but its not the end of the world if you get things wrong, as long as u test all your ideas just to make sure of the missing details.
The problem people have with you isn’t your lack of knowledge (because indeed we all started at zero), but your attitude.

Despite the fact that your level of knowledge is… limited (and that rather than filling the gaps with “I don’t know”, you’ve filled them with your own hypotheses), you act as though you were an expert, making incorrect proclamations and telling others (who do know what they’re talking about) that they’re wrong, when in fact it’s you who is wrong.

Before you start schooling others, you need to:
a) expunge your brain of all the answers that you’ve simply made up (as they are not a viable foundation for subsequent learning), and
b) learn a LOT more (as in formal learning, not just experimenting and conjecture)
 
The following users thanked this post: Zero999, george.b

Offline fourfathom

  • Super Contributor
  • ***
  • Posts: 1849
  • Country: us
Re: Load between battery and capacitor
« Reply #43 on: November 26, 2021, 03:57:36 pm »
To repeat myself, I think this "activating the diodes" is the root of this particular misunderstanding. Capernicus, please study it a bit more.  I think you will find that you have it wrong.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Online Zero999

  • Super Contributor
  • ***
  • Posts: 19344
  • Country: gb
  • 0999
Re: Load between battery and capacitor
« Reply #44 on: November 26, 2021, 07:05:47 pm »
I thought it was a possibility that the cap could discharge through the diode bridge because the ac power was activating the diodes,  but it turns out another one of the diodes stops the cap discharge separately.
If you got diode property wrong then clearly you would want to learn ALOT before even trying to spread your (clueless) wisdom in "I know it all" style.

[edit] Oh, and I am not even talking about ridiculous circuit with two series diode short in it...

My model of electricity is incomplete and approximate,   if yours is too I wont attack in the forumm of saying that it doesnt work most the time anyway,   everyone has their little guesses of whats going on,  sometimes it works out, sometimes it doesnt,  the ending details of what actually happens I think 99% of ppl get it wrong (so u have to do experiments to proove ideas.),  so I dont get anything perfect myself either, and I think that's all you need to get your machines up and running, being perfect would be good but its not the end of the world if you get things wrong, as long as u test all your ideas just to make sure of the missing details.
There are a few people here who understand how diodes work, down to the electron level, but even I know that you're wrong.  99.99% of people here don't get it wrong. Those who do was probably in the minority here.

As mentioned above. You need to change your attitude. It's fine to make guesses, but stop acting as though you're certain, when you're just making assumptions.
« Last Edit: November 26, 2021, 09:22:28 pm by Zero999 »
 
The following users thanked this post: tooki, george.b

Offline fourfathom

  • Super Contributor
  • ***
  • Posts: 1849
  • Country: us
Re: Load between battery and capacitor
« Reply #45 on: November 26, 2021, 07:53:41 pm »
[...] as long as u test all your ideas just to make sure of the missing details.

The problem here isn't a missing detail though, but a complete misunderstanding of a fundamental principle.  Hey, I had to learn this stuff too.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 
The following users thanked this post: tooki, george.b


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf