Understanding Electronics Basics #1

[Muttley600]

Morning CBB
That looks a bit more technical than my sim.lol but least I had a go
Nearly lunch time so I'll have a proper look in a bit

Now about learning from your mistakes & being married 3times.lol
I solved that straight off, I just didn't get married.....haha although spent last 13yrs with Lou

 

[cowboybob]

That looks a bit more technical than my sim.lol but least I had a go

Yes, you did.

And you did a fine job under the circumstances. You certainly proved to me that you've got a handle on TINA and most of the basics for where we're at, at this time.

This may be a bit of a stretch, but I think you're up to it.

CBB

 

[Muttley600]

I'll be fine with it, I'm enjoying learning, to be honest I'm struggling more with the math than the practical stuff, I was impressed with my sim because I knew I didn't know what components to use but I think I got the wave (or nearly) that you asked for
I've got to get my head around the sums but steadily understanding in my way, if it takes kids video teaching to understand then so be it

Ok, had a look at new sim, so you have basically put all those R/caps & switches in to save keep altering the values of each one

 

[cowboybob]

so you have basically put all those R/caps & switches in to save keep altering the values of each one

Correct. So that you can see the instantaneous changes (that result) on the scope. Sort of a "live" demo.

Observe how the DC (VF1) signal is altered by the changes, especially after you get it "clean" with the filter caps and then add load values (which messes it back up again).

What are your thoughts on way that happens?

 

[Muttley600]

Thoughts from what your saying initially as I'm at work til 7ish & cannot make sim would be that cap values need to be higher to cope with load, if that is what is messing with signal, however my answer is a guess at best until I get to play
But as you have give me varying options, we may be able to use two caps?

 

[cowboybob]

Well, not to give away the end of the story, but you've nailed it.

Go ahead and play with it any way. The switches just make the value changes more immediate and the results quicker and easier to see. Nothing to prevent you from making changes the normal way.

And, of course, the operative question is: "why" does a larger cap value allow the circuit to better deal with the load?

Plus, it'll give you some more experience with the scope.

 

[Muttley600]

The bigger the cap, the more charge it has, the bigger the load, the quicker it eats it hence small cap not enough

Nearly done for the day, quick coffee & I'm outta here (work that is), you know I'd still make sim anyway, have you known me let anything go yet.lol

 

[cowboybob]

Excellent.

 

[Muttley600]

food scoffed now time to play **broken link removed** I'm more curious now as to what will happen with too big a cap

Well heres the results before I read on

View attachment 61983View attachment 61984View attachment 61985

View attachment 61986View attachment 61987

 

[Ratchit]

Muttley600,

The bigger the cap, the more charge it has....

Nope, a larger cap contains the same net charge as a smaller cap with the same voltage across it. A cap with a higher voltage across it it has the same net charge as another same size cap with a lower voltage across it. A larger cap with the same voltage across it as a smaller cap stores more energy. A cap with the larger voltage across it stores more energy than another one of the same size with a lower voltage across it. In all the above situations, the net charge stored in the capacitors is zero, but the stored energies are different. A capacitor is an energy storage element. You don't "charge" a capacitor, you energize it.

Do you understand the above?

Ratch

 

[KeepItSimpleStupid]

Time for me to disagree again. This app note: https://www.electro-tech-online.com/custompdfs/2012/03/dn450f.pdf specifically uses the words "Charge a capacitor".

 

[Ratchit]

KeepItSimpleStupid,

Time for me to disagree again. This app note: specifically uses the words "Charge a capacitor".

Yes, and NASA astronauts "walk" in space instead of float. They sure would look funny moving their legs while going nowhere. And you use the phrase "current flow" which means "charge flow flow".

Just because inaccurate terminology is used in reputable publications or common discourse does not make it correct.

Ratch

 

[Muttley600]

Nice signiture ratch

KISS used to pick me up, then he realised I was just tooooooo heavy.lol

On the morrow guys, hope you sleep tonight KISS

 

[cowboybob]

I'm more curious now as to what will happen with too big a cap

In a practical sense, too "big" a cap is not a problem.

What you look for is a filtering network that keeps the AC "noise" caused by inadequate filtering from expressing itself on the power supply's DC output, given the power requirements of your "end-using" circuit's purpose(s).

Why, you ask?

The AC ripple riding on a DC level can, in certain circuits, "contaminate" the so-called "DC bus"; the main power for the circuit components. That being the case, this ripple can (especially in biasing or reference sub-circuits) cause premature triggering, false rise times and even phase/frequency shifting errors. In strictly "on/off" situations it can cause "chatter" in the switching circuits which can have totally unacceptable responses from many digital devices.

Or more simply it would result in an annoying 60 (or 50) Hz hum from an amplifier's speakers.

The point being that the "cleanliness" of a DC source (a battery being the ideal, for the most part) is predicated by the circuit design purpose and your expected output.

Looks like where we can go from here is to "mate" your AC generator to the rectifying/filtering network and make a DC to DC converter.

It may end up looking over-engineered (some may even say crude) and impracticable, but it'll be something you created.

CBB

 

[Muttley600]

Ok, you know I need to ask this question, why do they make small caps?

Morning CBB

DC to DC converter sounds good, your giving me the info I need for project bit by bit aren't you, meaning I'll actually understand why the components are used.......I knew you understood what I wanted from this project
& hopefully this is just the start of many more, I may even get to understand the formulas at some point too.lol

Reading your post again, your saying that AC can affect DC, I take this wouldn't be such an issue with wires (but still happens to a degree) but on board it has the potential to upset things due to bad design, not filtered properly. So with the potential to jump on other line & directly affect the outcome you were hoping for

 

[cowboybob]

Morning Graham.

Ok, you know I need to ask this question, why do they make small caps?

That's a loaded question. Caps are used in lots of ways beyond filtering. I'll give a more detailed answer in a bit.

DC to DC converter sounds good, your giving me the info I need for project bit by bit aren't you, meaning I'll actually understand why the components are used.......I knew you understood what I wanted from this project

Yeah: there was a method to the madness...

 

[KeepItSimpleStupid]

Capacitors are frequency dependent and they do other things. LeCroy has just creataed a 60 Gigahertz bandwidth oscilloscope. http://www.lecroy.com/ Not an easy feat.

 

[cowboybob]

Un--be--lie--va--ble

They're finally packaging magic...

There's no limit, is there??

 

[Ratchit]

KISS,

Capacitors are frequency dependent ...

No they are not. Their capacitance stays the same until secondary effects start to occur.

LeCroy has just creataed a 60 Gigahertz bandwidth oscilloscope.

I am sure their marketing department approves of your announcement. Anyway, they need two channels to achieve that bandwidth.

Ratch

 

[Muttley600]

Back from work, so about this DC to DC converter, are you on about DC to AC then back to DC or putting something from AC gen

oh, you've both legged it, that's good I'm shattered, busy day today, think I'm gonna treat myself to nice soak in the bath before walking bobby