# Industrial electronics: Unclear symbols

1. Sep 12, 2011

### Femme_physics

1. The problem statement, all variables and given/known data

So in this circuit
http://img850.imageshack.us/img850/5061/circuittoregulate.jpg [Broken]

Given that alpha = 60 degrees

I'm asked to draw qualitatively Vin, URL, UAK, and IAK.

Now Vin and URL are simple, but what ARE UAK and IAK? What are they? I don't see an "A" point on a circuit nor a "K" point

Last edited by a moderator: May 5, 2017
2. Sep 12, 2011

### Femme_physics

Last edited by a moderator: May 5, 2017
3. Sep 12, 2011

### I like Serena

Hi Fp!

Don't you have a list of abbreviations in your course material?

Anyway, I've just looked it up.
See http://en.m.wikipedia.org/wiki/Thyristor
It has a pic showing the Anode and Cathode (aka Kathode).

Last edited: Sep 12, 2011
4. Sep 12, 2011

### I like Serena

This is going to be soooooo messy with 3 problems in 1 thread.
I'm sure we will all be very confused very soon which problem/picture belongs to which post.
Can I suggest you make separate threads for them?

Hmm, you removed the diodes. I guess that's ok as long as you keep careful track of the direction of the currents. As it is, I'm afraid you didn't. I3 can't flow the way you drew it.

Furthermore, you have drawn the 2 batteries in opposite directions, but that is never so.
You have 2 cases, but in each case the batteries must be in the same direction.

Finally, your 3rd equation is redundant. It is effectively contained in the first 2 equations.
That's the reason your calculator does not accept it.
You should add a KCL equation though...

Last edited by a moderator: May 5, 2017
5. Sep 12, 2011

### I like Serena

Oh, the 3rd problem is a double-post....

6. Sep 12, 2011

### I like Serena

As for the SCR problem, the element doesn't quite work like a regular diode.

Under normal circumstance it blocks in *both* directions.
It's only when a pulse is given on the "Gate" that current can flow through, in the regular direction of the diode, and then only as long as the voltage is up to keep it flowing.

When the voltage gets negative it blocks again in both directions.

7. Sep 12, 2011

### Femme_physics

hehe....hey ILS!

Ah, you're right, I suppose this is exactly why they gave us alpha - the angle of ignition

What do you mean by "pulse"?

And where is the gate? Is it the long horizontal line at the end of the triangle's tip?

Be back in 4-5 hrs

8. Sep 12, 2011

### I like Serena

Yep!
I've been swimming ON the water. It's never been so easy to do a crawl (as long as you keep you face well above the water - you really don't want water in your eyes!)

And what's really weird, is that there are lots of Dutch people here! :surprised:!!)

And I've found a computer terminal at the reception, that makes this *a lot* easier.

Huh?
As yet this has nothing to do with alpha.

In this picture you can see how it behaves.
The bottom graph shows what a "pulse" looks like.

Yep, as you can see in this picture:

Good that you mention that!

But... does that mean you want to do more work late in the evening?

Last edited by a moderator: Apr 26, 2017
9. Sep 13, 2011

### Femme_physics

Got it :) ]

Ended up falling asleep ^^

Oh right, where alpha is the ignition angle.

hehe gOod to know

Good! and thanks.

About to leave for the test soon. thanks for everything!

10. Sep 13, 2011

Good luck!