[sdiy] Hollow low-pressure ladder filter

[René Schmitz]

At 17:11 28.04.02 -0700, John L Marshall wrote:
>12U7s were designed for car radios, 12 volt plate supply, 30 volts maximum.

Right, these were meant to be used in the RF parts of the radios. 
I.e. usually a tuned circuit as late load. Back when transistors had sluggish 
highfrequency properties.
I've got some battery tubes here (direct heating 2V, 60mA) which work good on 
low voltages. I once built an audion receiver using one of them, the plate 
was powered by a single 9V block. But the gains you can archeive are smaller 
than with higher voltages, and you have to use higher impedances, because
there 
is only a plate current of a couple hundred microamps.

Cheers,
 René



-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159