Hi, really struggling to make a 3 way switch work in lt spice, any help much appreciated!

Have don't everything suggested that ive read in other forums but nothing has worked. Attached are images of what I have got and the switch file.

The idea being each variation of the 3 is run.

 

hi gb,
Welcome to AAC.
Please post your asc file, so we can see what you have so far.
E

 

Here is my file so far. This is to be part of a larger circuit. The idea is to be able to choose between having either 1, 2 or 3 of the JFET's engaged to get a different level of distortion from each one. Just need a switch to swap between the 3 outputs!

Thanks for any help

 

not sure if this is needed too!

 

hi gb,
I see what you are trying to do, I get a 'missing nodes' error when trying to run your asc file.
I will look it over.
E
Posted a clip section of your file, for reference.

 

Yes thats the same error that I get! Have tried a bunch of things and also edited one of the stock voltage controlled switches but with no luck. That would be amazing if you could look into it, thankyou!

 

hi,
There are a number of LTSpice users at AAC, one of them may already have a suitable 3 Pole switch,
I already have the regular 1 and 2 way switches, see if I can create a 3W model.
E

@Bordodynov
@Alec_t

 

hi,
There are a number of LTSpice users at AAC, one of them may already have a suitable 3 Pole switch,
I already have the regular 1 and 2 way switches, see if I can create a 3W model.
E

@Bordodynov
@Alec_t

Thanks for all the help. If you did also have 2 way switch the would be very helpful as I will also need one of those for something else!

 

hi,
This zip has my switch files.
E

 

Here are my switch files. They are voltage-controlled switches, with a control voltage in the 0V to 1V range. The ones with 'bm' in their name are break-before-make, whereas those with 'mb' in their name are make-before-break. For the 3-way switch, a control voltage between 0.34V and 0.65V selects the middle way.
Have fun.

Edit: Oops. forgot the SP3Tvc.sub file.

 

I think your 1P3T.sub file in post #4 needs modifying to work with the .asy file you posted.
The sub fle currently reads:

.subckt 1P3T 1 2 3 4
R12 1 2 { IF ( SET < 2, 1u, 1T) }
R13 1 3 { IF ( SET <= 2 & SET >= 2, 1u, 1T) } ****
R14 1 4 { IF ( SET > 2, 1u, 1T) }
.ends 1P3T

The line I've marked **** seems illogical, and the model does not have a node labelled 'out' as used in the .asy file..

Try this, which should work with SET=1,2 or 3:

.subckt 1P3T out 1 2 3
R12 out 1 { IF ( SET < 2, 1u, 1T) }
R13 out 2 { IF ( SET <3 & SET >= 2, 1u, 1T) }
R14 out 3 { IF ( SET >=3, 1u, 1T) }
.ends 1P3T

 

Thanks for all your replies. I had been working on a cruise ship and out at sea so could not download the files to try! But I have now...
unfortunately I have tried both of your switches with no luck. Also tried putting in the new .sub file recommendation from Alec. It always comes back with a missing nodes error. Is this potentially a formatting issue because I use a Mac?

I have also tried to edit the voltage controlled switch in the program already. This is after advice from this forum a long time ago here: It seems pretty good, but I get an error saying there is a pin count mismatch between the sub circuit spdt and the instance xspdtswitch.

My file is attached!

 

This is where the advice came from in order to ditch the current voltage controlled switch in case it helps btw: https://electronics.stackexchange.com/questions/372278/spdt-in-ltspice

 

hi gb,
Tried your asc file on two PC's one with LTS IV, I get 'Unkown schematic syntax' , on the other PC LTS XVII ' I get message 'missing potentiometer.sub.'

I am working on a 3 way version of a switch, finding difficult to control the selection, still trying.

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Ah I should have included the potentiometer stuff. Also good to have if you ever need one! Its attached now, cheers!

 

hi,
I do have a copy of the pot files in the XVI version , downloaded your version into the XVII version.

I get the same message as you' Set: Missing Nodes' , I will try to debug it.
E

 

hi qb,
Reading what the result you aiming for ie: is producing a wav file for the 3 different gain stages, why not just 'hardwire' the asc file for each stage in turn and then run it for each connection.?

This will give you the 3 distortion levels as wav files.
E

 

Hi

Try this switch.

Unzip the .zip file so the .asy and .asc files are in your schematic folder.
Remove the other switch and params.

Add the switch and params and Connect it like shown below:



eT

 

On your schematic you have "inc. 1P3T.sub". That is not a valid directive. It should read ".include 1P3T.sub".

 

thanks for all the help everyone... I finally have working 2 and 3 way switches! Thanks eetech00 your switch worked a treat! Really appreciate everyone putting in the time to help a frustrated newbie out ))