Nodal current controlled voltage source with multisim

Thread Starter

KevinEamon

Joined Apr 9, 2017
281
Excuse for the injuriously long winded title. A summarized description of my various woes and joys of the day.
So, I thought I had this nodal, with dependent voltage source cracked. I went and tried to find a few solved examples, however it's surprisingly difficult to find something that matches what I need. Also many that the commentators are saying the people in the videos are definitely wrong.
PANIC ATTACKS - 4 days to go till exam... not good

A older student recommended I try multisim and loaned me his multisim13 version.
A great tool indeed. Though I'm struggling with these controlled voltage sources.
Pulling the wires round all sorts of spirally crazy directions, I just don't like it... and I'm not entirely sure i'm doing it right.
So I found out about the AMB

I wanted to design the circuit in this thread
https://forums.ni.com/t5/Multisim-and-Ultiboard/Current-Controlled-Voltage-source/td-p/2867600

Now I have no idea what the heck this means
5*(V(1)-V(0))/2
When I first researched this ABM it seemed to me that - you could click on the piece of wire you wanted the current from. Call it something in "preferred net name" say for eg. " i "
Go to the value of your ABM 5(i). Boom dusted...

I mean how simple would that be ?

But no... sigh...

You know all I need?
Something like this here circuit up here solved. So I can see if I'm doing it right. But I'd probably like to know how to use this here thing too.
 

Thread Starter

KevinEamon

Joined Apr 9, 2017
281
Might be helpful to see this method I've been using - I found it off ta internet. Seemed good. And I've been using it a while.

Maybe I'm doing it slightly wrong or something
 

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MrAl

Joined Jun 17, 2014
7,590
Hi,

I can take a look at your circuit a little later unless someone else does first.

in the mean time, when you see something like this in the context of a simulator:
V(1)-V(0)

it usually means the voltage at node 1 minus the voltage at node 0. It's that simple, but you have to know your node numbering which you can usually find out with the software you are using. So you can look at it as:
V1-V0
if we labled node 1 with V1 and node 0 with V0.

Similarly:
5*(V(2)-V(1))/2

means the voltage at node 2 minus the voltage at node 1, times 5 and divided by 2.

Of course this means that if V(2) was 10v and V(1) node was 8v, we would get:
5*(10-8)/2
5*(2)/2
10/2
5

so that expression would evaluate to 5 volts.
 

Thread Starter

KevinEamon

Joined Apr 9, 2017
281
It's ok panic off. I'll look at multi sim later. Doing it the old fashioned way I have some books from the library. One of them must be the real old fashioned way - the resistors are labelled :- "s" like 2s... Lul old people are really old :)
 

MrAl

Joined Jun 17, 2014
7,590
Hi again,

Never have i seen 2s for a resistor, but i forgot to mention that if we use:
V(2)-V(1)

that gives us the voltage between nodes 2 and 1, but if later we add more nodes with more parts we might see the schematic node numbering change. So that means it might change 2 to 3 and 1 to 2 for example. The software should show this though. In a model definition it only changes if you change it yourself either directly or by reassigning pin numbers, or at least that's the way it works in spice.
 
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