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VX-86 sub-min toob -data?
Hi all -
No, i don't think it's mic toob & I'm suddenly rich, but I couldn't find any data on this toob. It's a sub-min tetrode (strapped as a triode in the circuit), made by Victoreen, the date code implies that it was made in mid-'62. Judging by the circuit (Geiger counter with the tube attached right to the ionizing chamber), it's *got* to be a high-gain tube, and I'm calling it a tetrode just 'cos it has 2 grids - perhaps the intent of the second grid is ... ? Does anyone know the tube, or where I could find some data? Thanks in advance... -dim |
#2
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shiva wrote:
Hi all - No, i don't think it's mic toob & I'm suddenly rich, but I couldn't find any data on this toob. It's a sub-min tetrode (strapped as a triode in the circuit), made by Victoreen, the date code implies that it was made in mid-'62. Judging by the circuit (Geiger counter with the tube attached right to the ionizing chamber), it's *got* to be a high-gain tube, and I'm calling it a tetrode just 'cos it has 2 grids - perhaps the intent of the second grid is ... ? Does anyone know the tube, or where I could find some data? Thanks in advance... -dim What you have is an 'electrometer' tube. It is used where a very high input impedance is required, as in some measurement equipment. The gain is not particularly high. The tube acts as an impedance convertor. Grid one is run slightly +ve. The input potential is applied to grid two. Victoreen made a lot of stuff like that, including precision very high resistance resistors, ie, 1000 megohms, Etc. If you like I will post more info on ABSE ref the tube. John Stewart |
#3
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"John Stewart" wrote in message ... shiva wrote: Hi all - No, i don't think it's mic toob & I'm suddenly rich, but I couldn't find any data on this toob. It's a sub-min tetrode (strapped as a triode in the circuit), made by Victoreen, the date code implies that it was made in mid-'62. Judging by the circuit (Geiger counter with the tube attached right to the ionizing chamber), it's *got* to be a high-gain tube, and I'm calling it a tetrode just 'cos it has 2 grids - perhaps the intent of the second grid is ... ? Does anyone know the tube, or where I could find some data? Thanks in advance... -dim What you have is an 'electrometer' tube. It is used where a very high input impedance is required, as in some measurement equipment. The gain is not particularly high. The tube acts as an impedance convertor. Grid one is run slightly +ve. The input potential is applied to grid two. Victoreen made a lot of stuff like that, including precision very high resistance resistors, ie, 1000 megohms, Etc. If you like I will post more info on ABSE ref the tube. John Stewart Hi John - If you could, it would be great. This thing's sitting in a kind -o sort - a Geiger counter - A Civil Defense thingy from the late 50's (last cal date 69) a steel ionization chamber, inside of a steel case, with the pickup hooked up right to the grids (jumped) of the tube. I guess the kind of a thing you kept in your "fallout shelter", waitin' for us pesky ruskys to drop the big'un. I got the transistor oscillator going (it feeds of 1 C cell), and the thing seems to be working now, though I have no way to test the ionization chamber - Since it's basically a tin can inside of a yeller metal case, I assume it only measures the "hard Stuff" (Gamma), and i can't think of anything commonly available that produces enough gamma to make the meter move. Thus far the only thing i've done was make the needle jump by touching the grids. I have a '40's navy electronic tech book, and it describes a bunch of radiation meters (down to photo paper...), but they all have a sample for calibration - this one doesn't. Looks like a "homeowner" model, with a CD stencil on the side - not a precision chunk 'o gear. Anyhow, one of those "broken things to fix - but now what?" deals - thought it might be a fun tube to play with... I've got an old grid leak meter I never use, that's got some sub-mini toob in it too - though I guess I should do something more productive, like comb out my black cat - of all the cats, he's the biggest shedder... the keyboard is covered with cathair... -dim |
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