I am new to Ltspice and cant seem to update or add to the library,there are no voltage regulators or relays, photo transistors, in fact its pretty useless to me at the moment, how do you add extra libraries and from where?

Thanks

 

Here you can find all the additional models
http://tech.groups.yahoo.com/group/LTspice/

http://valvolodin.narod.ru/soft/extra.rar
http://forest22.homeip.net/Electronics/index.html

Unpack the archive "extra.rar", using the archive RAR
Copy "extra1.rar" which is installed in the directories are LTspiceIV. Typically, this directory is "C: \ Program Files \ LTC"
Unzip "extra1.rar" which is installed in the directories are LTspiceIV

 

Here you can find all the additional models
http://tech.groups.yahoo.com/group/LTspice/

http://valvolodin.narod.ru/soft/extra.rar
http://forest22.homeip.net/Electronics/index.html

Unpack the archive "extra.rar", using the archive RAR
Copy "extra1.rar" which is installed in the directories are LTspiceIV. Typically, this directory is "C: \ Program Files \ LTC"
Unzip "extra1.rar" which is installed in the directories are LTspiceIV

Thanks for that , but there are still no photo transistors, transformers, variable capacitors

 

Transformers are done with paired inductors and a coupling parameter. Watch the polarity dots for phasing. See the threads in the yahoo group for this. You can make your own graphic if you like for the variable capacitor and then have a parameter that can be swept over a range or assigned values from a list. Again search the threads on the yahoo group for "Variable Capacitor". Photo transistor I'm not sure about, but I'll bet Helmut S. has an answer for you. Ask him.

Also -- read the help files. There are many tips there.

 

In LTSpice, go to File -> Open -> examples -> Educational; look at Transformer.asc, Transformer2.asc, and IdealTransformer.asc

Note that you can specify the resistance of a winding either directly in the inductor, or using an external resistor (like R1 in Transformer.asc); I prefer to use resistance in the inductor.

Note that in the coupling parameter:
Kn L1 L2 {...Ln} coupling
that you can specify less than 1 for coupling, but it will take far longer for your simulation to complete. I usually simply specify 1 for coupling.

 

In LTSpice, go to File -> Open -> examples -> Educational; look at Transformer.asc, Transformer2.asc, and IdealTransformer.asc

Note that you can specify the resistance of a winding either directly in the inductor, or using an external resistor (like R1 in Transformer.asc); I prefer to use resistance in the inductor.

Note that in the coupling parameter:
Kn L1 L2 {...Ln} coupling
that you can specify less than 1 for coupling, but it will take far longer for your simulation to complete. I usually simply specify 1 for coupling.

How do i create a photo transistor, and motor?

 

You might start by looking at optocouplers. Each optocoupler has a photo transistor as the output stage. Some optocoupler models bring the base lead out and that may be the way to simulate a light to current converter. You could also use an optocoupler and simulate the light input with the LED.

I'm guessing the motor will be similar to the transformer electrically. What I'm not clear on is if you can synthesize a current to "shaft position" or "shaft velocity" device.

The guys on the yahoo group will have more current information than I do. You need to go there first.