dia diode deli?

If it is possible to pass only the negative current, what diodes should I be looking for?

I'm pretty certain its a no-no in circuitry design.

and I've never seen a symbol "-<|-" or (-1A)---<|---(+1A) which would represent the idea --syntax-correct.

anyway, it might seem an obvious thing to assume a positive orientation to all the old hands at design, but to someone new like myself, it's not so obvious.

the thing is, do such diodes exist, or are they called something else?

Why not go to Radio Shack, buy a diode, and put a multimeter on it with it set for continuity? Does it beep in both directions?

Then come back here and tell us.

Oh, and I thought that there're expert in here. I was sure the experts would have had something to say, if indeed there're any floating around these halls.

I have a multimeter, but I don't have any diodes to test.

But the question was more about the designing and circuit representation, or more to the point, the correct methodology. As well as the second representation... "-<|-" and if such a configuration exists. Its almost a capacitor.

And you went to the cupboard and found nary a diode for your poor dog! Do they let you out? Can you go to an electronics shop or by a fifty cent diode off the web?

There are some really good EE's here, they just haven't gotten around to your question or need more information. Patients. All will be revealed to you in due time. You might want to think about rephrasing your question while you wait.

We are just the dork vanguard!!!

50 cents? A 1N4001, being a 1A rectifier with a 50V reverse voltage rating, can be had in the UK for £0.04!

So who much is that in Euros?

I am very sorry but you have to explain more .first of all what symbols are these (-1A)--->|-------~-----(+1A)

>>>(+1A)--->|-------~-----(-what do you want to say by <<a diode be used to limit ...>> you mean to pass the current in one way and at the same time to have a drop in voltage??? If the answer is yes there are many ways to do that

Give us more information.

First: go and get a free copy of TinyCAD.

http://tinycad.sourceforge.net/

Now: I'm not sure if this answers your question.

Current will not flow through the load resistor in the top picture but will flow in the bottom picture.

ah!!! so its not exactly wrong to write it as the above method if your intent is to stop the flow.

yeah, close enough.

Thanks Randall.

Electrical current is by convention assumed to flow from negative to positive. In a metallic wire where current is carried by loose electrons, the electrons actually move from negative to positive. Semiconductors are poor conductors. They come in two types. In N type semiconductors, current is carried by electrons. In P type semiconductors, current is carried by vacancies or holes where an electron is missing. (Think of an almost full auditorium where someone moves into an adjacent vacant seat. The vacant seat appears to move in the opposite direction.)

In a diode, a piece of N type semiconductor is joined to a P type semiconductor. If voltage is applied in the "forward" direction, the electrons in the N type move to the junction and the holes in the P type move to the junction. When an electron meets a hole, the hole is filled and cancellation takes place. This process continues as long as current flows in that direction.

If the voltage is reversed, the electrons in the N type and the holes in the P type flow away from the junction. The diode acts like a capacitor and no current flows after the charges are separated.

Electrical current is by convention assumed to flow from negative to positive.

Sorry, should be positive to negative.

if ya study Electron Theory, it goes from Neg to Pos

I can't draw a straight line so I don't try. BUT I have used diodes in 12 volt dc circuits for years. ie switch A turns on light A. But switch B turns on light A and B. Diode is connected between light A and B. If the diode is reversed it will operate as follows. Switch A turns on lights A and B. Switch b turns on light B only. There is a voltage drop across the diode when used in this fashion. I thought it is 7/10 of a volt at 12 volts. One last note be sure the diode is able to handle the load of the device. Good luck.

thank u Bob. Great one

some good pointers in there, and it does do what I expected. thats a huge voltage drop.

Good luck back

Hi Guest,

Bob meant 0.7 V not 7 to 10 V

Randall

Bob was very clear.

cheers

what Bob didn't mention is that the flow should be depedant on the flow over impediance ratio. so selection of diode values is crucial to stem the flow completely or allowing a decreased value to flow

But in invoking impedance, you're talking about AC heading into the diode?

you didn't keep up with the mode of exchange, "backward rigged diodes"

It was my belief that diodes conduct in only one direction and only in the positive? That's why they are used to rectify AC into DC. However, you're talking about putting current in the opposite way? What happens then?

Sorry if I'm slow.

Yeah, thats what the nature of this thread is about, backward rigged diodes. as for what happens, read above.

The reason I didn't mention the impediance radio is because we get such bad reception that I just turned the dang thing off.

I didn't mean anything by "failure to mention". I just furnished a bit more information about expected diode behavior.

Though I'm puzzled as to why reception has anything to do with diode and current values.

Vermin, tell Del to Back the off.

"Vermin, tell Del to Back the off." should be Vermin, tell Del to Back them off

Huh?

Diod is a unidirctional current leading device. This device can conduct electrical current from the high vlotage side to lower voltage side. But so far as the DC current is concerned it has only one side. It doesnt include bothe positive and negative sides to gether. Diod doesnt conduct from lower voltage side to the higher voltage side.

Please give a clear message. Can't make out your question

I too cannot discern anything of the originators "-<|-" or any of the other. Like Greek or something.

I agree that perhaps that this may be resolved easily with a diode method, but maybe the task involves more than expressed.

If the originator can't find Radio Shack or other, I'd be glad to mail (U.S. only) him a 1N4004 (1 ampere, 1KV, good to much of anything below those parameters) silicon diode so that he can determine it might do the trick.

Sure are a lot of "Guests" in this Forum and other. Sometimes difficult to figure out who's saying what to whom.

I have no problem getting diodes thanks. 0.10 each

maybe when I have space, I'll join and get a name. not now though.

Time is time. Sometimes forms a sense of sincerity. Like intoducing one-another in public.

Clarification on the graphical script "+/-" ?