need a program to simulate in electronics

[walid]

Hi
please I want the program to simulate in electronics to perform some tests on the transmitter and receiver
thanks

[audioguru]

Hi Walid,
I am learning the Sw CAD III simulation program by Linear Technology Corp. It is free.
It has a pretty big library of components and it is updated frequently. There are a few websites with add-on P-Spice models for many more components for it.

[Steve_hi]

http://www.linear.com/designtools/software/switchercad.jsp

[Master_Ianick]

hi, you can get MULTISIM 9! That is very good and very simple program to simulate circuits..

try :D

GoodLuck!:D

[walid]

hi guru

It has a pretty big library of components

not at all, for example there is no variable cap and no transformer .....
how to get these parts?

To Master_Ianick , thank you very much

To Steve_hi , thank you very much

[AN920]

In help files of SWcad

[walid]

Hi AN920
You are good person , I benefited greatly from your help, thank you from the bottom of my heart .

What if I want to make a center tapped transformer at one side, how to simulate it.

[AN920]

Hope this helps.

*
L1 N003 0 1mH
V1 N003 0 SINE(0 100 1000) AC 10 0 Rser=10
L2 N001 0 100

[AN920]

If you wanted the circuits to be isolated, you may do something like this. Spice needs to see some path to circuit GND otherwise you will get an error. You may make the resistor much higher in value.

[walid]

Dear AN920, I do not find the right words to express to you my deepest thanks and respect. thank you very much.
questions:
(1)The transformer Comprising L1, L2 and L3 have DOT at the bottom of each coil.
  I remember I studied something of this kind before, but now I forgot its purpose, can u please tell me, and what happen if we reverse one of them?
(2)I see a command line: K1 L1 L2 L31, i know K1 is the mutual inductance and      L31 is the inductance affect L3 due to current pass through L1. but how to write this command and how to choose those values? 

NOTE: There is a small problem in the program which is the nodes numbers that appear in the graph didnot shown in the circuit, and one can't know some graph belong any node. 
Thanhs

[audioguru]

NOTE: There is a small problem in the program which is the nodes numbers that appear in the graph didnot shown in the circuit, and one can't know some graph belong any node.   

I also noticed that the node numbers are not shown on the schematic.

[AN920]

I am not an expert with this program as I hardly ever use it. I find the user interface too clumsy and drawing large schematics a pain. There should be some option to display the node numbers on the diagram. You can go "view spice netlist" as another option.

The dots indicate the phasing of the coupled inductors.

From help file

K. Mutual Inductance


Symbol Names: None, this is placed as text on the schematic.



Syntax: Kxxx L1 L2 [L3 ...] <coefficient>



L1 and L2 are the names of inductors in the circuit. The mutual coupling coefficient must be in the range of -1 to 1.



The line



K1 L1 L2 L3 L4 1.



is synonymous with the six lines



K1 L1 L2 1.

K2 L2 L3 1.

K3 L3 L4 1.

K4 L1 L3 1.

K5 L2 L4 1.

K6 L1 L4 1.



It is recommended to start with a mutual coupling coefficient equal to 1. This will eliminate leakage inductance that can ring at extremely high frequencies if damping is not supplied and slow the simulation. However, a mutual inductance value of -1 or 1 can lead to simulation difficulties if the uic directive is flagged on the .tran card.