I am reading about the Atanasoff Berry Computer (ABC).

It used over 200 6C8G dual triodes (and a bunch of thyratrons).

I found a specification for the 6C8G and a picture of it. They do not agree on the connections!

The data sheet shows an 8 pin octal yet the photo shows a top cap. See the attached PDF's for what I found.

Can anyone help solve this dilemma?

 

The datasheet says the cap is the grid for Triode #2. Just underneath the coding for pin 8.

 

Dilemma?

Your first data sheet shows a top cap connection for Grid Triode T2.
Your second pdf shows a photograph of the tube with top cap connection.

 

The datasheet says the cap is the grid for Triode #2. Just underneath the coding for pin 8.

Thanks, that was quick.
I see it now. It looks a lot like the key on the diagram so maybe that is how I missed it. I also expected the top cap to be a plate since that is all I ever remember seeing.

Now back to understanding how the ABC regenerative memory works.

 

Dilemma?
Your first data sheet shows a top cap connection for Grid Triode T2.
Your second pdf shows a photograph of the tube with top cap connection.

Not a dilemma any more. Thanks.


You guys a really fast showing how slow I am.

 

OK. Another related question...
Why add a top cap when pin 1 is unconnected?

 

OK. Another related question...
Why add a top cap when pin 1 is unconnected?

Compatibility with other tube pinouts

 

One final (?) comment.
I looked closely at a picture of the ABC adder unit and it does show tubes with top caps.