LS50.....GU50 Translation Please

[pl802]

Thanks

 

[Kay Pirinha]

"Durchgriff" = (1/mu) x 100%

So 20% corresponds with mu = 5 and 0,35 % with mu = 285

Edit: I am not so sure about the max. idle current of 30 mA in triode mode. That value looks too low to me. But this value appears in more datahseets (EL152, FL152, P50) so it's a bit of a mistery to me.

Edit 2: I found this so the 30 mA must be wrong.

Yes, you're right, µ =5 in the first table. I underwent a typo. Sorry for that.
Although you're also right with your calculation for the 2nd case, I can't believe this is really true with that valve. I suspect that TELEFUNKEN's datasheet isn't correct, as µ = 28.6 seems more plausible for an old tube like that.
Best regards!

 

[32860]

Hi Kay,

I think the 2nd case might be right. By connecting the control grid and the screen grid together, you get a zero bias triode. They can have very high mu.

I found some literature (Power Vacuum Tubes Handbook, Whitaker, Chapter 3.2.5) in which triodes with mu = 200 or higher are mentioned.

Greetings,
Robert

Edit: Mu = dVa / dVg. If you look at the curves i think mu = 285 is right. When you go from Vg = +2,5V to Vg = 0V, you have to 'bridge' more than 700 Volt of anode voltage.