I am trying to simulate an 50-year-old circuit that I am guessing used germanium transistors. (See below). The simulation works with 2N3904's but I want to get a better feel for how it might have worked with older parts.

I looked in LTspice Standard.bjt library at LTwiki and did not see any parts with a low enough number to be germanium.

Any ideas where I can find a model?

 

Hello,

Would this page be of any help?
http://www.diyaudio.com/forums/soli...np-germanium-transistor-spice-model-rare.html
It shows the spice models for the AC127 and AC128

Bertus

 

Hello,

Would this page be of any help?
http://www.diyaudio.com/forums/soli...np-germanium-transistor-spice-model-rare.html
It shows the spice models for the AC127 and AC128

Bertus

Thanks a lot bertus.

I will try using the NPN model in my circuit and see if it works. (If it doesn't then I suspect I will have to tweak the Ft in the model.)

edit: I found a data sheet here... Now all I have to do is learn to read German:
http://alltransistors.com/pdfview.php?doc=ac128.pdf&dire=_valvo

 

I am trying to simulate an 50-year-old circuit that I am guessing used germanium transistors. (See below). The simulation works with 2N3904's but I want to get a better feel for how it might have worked with older parts.

I looked in LTspice Standard.bjt library at LTwiki and did not see any parts with a low enough number to be germanium.

Any ideas where I can find a model?


View attachment 128961

There are many Russian sources of germanium component models, just Google the filename with the appropriate extension and sort through the hits.

Yahoo groups had a spice forum that might help if its still there.

Make sure your computer is secure before having anything to do with Yahoo!

 

There are many Russian sources of germanium component models, just Google the filename with the appropriate extension and sort through the hits.

Yahoo groups had a spice forum that might help if its still there.

Make sure your computer is secure before having anything to do with Yahoo!

Good idea about the Russians for germanium transistor data. I will check that out.

I always get the Wiki and Yahoo forums confused. I will try the Yahoo forum as well.

 

Hello,

I do not kow if there are any models for them on the ltwiki:
http://ltwiki.org/index.php5?title=Main_Page
Or in the additional libraries (there is a ver large one made by our member @Bordodynov ):
http://ltwiki.org/index.php5?title=Components_Library_and_Circuits

Bertus

 

It is my library Germanium:

 

http://www.diyaudio.com/forums/solid-state/117257-BOGUSac128-pnp-germanium-transistor-spice-model-rare.html
It shows the spice models for the AC127 and AC128
Bertus

Bertus:
I tried the models at your link and they were bogus.

The first clue was that the models worked too good. I expected taht I would have to make some changes to the circuit.
The specification for the part (as I understand it) says the part should not have worked well at 1 MHz but it did.

@bertus could you please edit post #2 to reflect that these are bad models? This might help someone that happens onto this thread in the future.

Here is the proof that someone posted a silicon transistor model. Note that the germanium diode has a forward voltage of less than 200mv whereas the bogus germanium transistors have Vbe of over 650mv.

 

It is my library Germanium:

Thanks.
I tried your model for the AC127 and it does not work. This is what I expected.

I have to modify my circuit for the slower germanium transistor to see what happens. I will get back to you on this.

 

Thanks.
I tried your model for the AC127 and it does not work. This is what I expected.

I have to modify my circuit for the slower germanium transistor to see what happens. I will get back to you on this.

Spice models for AC127 and AC128 I made on a fairly detailed datasheet. I got a good correspondence with the datasheet. I tested these models and everything worked for me.
By the way. The models of germanium transistors are on ltwiki. This file is standard.bjt and the same (almost) file is in my large folder.

 

Spice models for AC127 and AC128 I made on a fairly detailed datasheet. I got a good correspondence with the datasheet. I tested these models and everything worked for me.
By the way. The models of germanium transistors are on ltwiki. This file is standard.bjt and the same (almost) file is in my large folder.

Thanks, again for your models. I had looked on ltwiki and somehow missed them.

The models seem to work in my simulation. There are some oddities but I don't have any reason to think it is the models. It is now up to me to understand everything I think I know about the circuit.