Re: Thyratron Tube

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "john cooper" <tesla-at-tesla-coil-dot-com> 

Does anyone have a use for an Arcturus 885 Thyratron Tube?  Is it even 
useful nowadays?  This is n.o.s., in its original box and must be 50+ years 
old.
 >
 >     To help some of us who don't know how to look up the specs, what are 
its:
 >
 >1. Voltage holdoff rating
 >2. Current rating
 >3. Is it hydrogen or mercury or ...?
 >
 >     Kinda doubting it's a monster since it was lumped with a bunch of 
other tubes, but it *might* be useful if its voltage rating is past SCR 
capabilities. Phil LaBudde

*********
I can't locate Arcturus data sheets but did find RCA, the electrical 
characteristics 'should' be similar, couldn't say for sure though.  Per the 
RCA data sheet:

Sweep-circuit service:

peak anode voltage = 300V
peak cathode current = 300mA
peak grid current = 1mA
peak voltage between any two electrodes or between any electrode and heater 
= 350V

Relay and grid-controlled rectifier service:

peak anode voltage = 350V
peak cathode current = 300mA
ave. Cathode current = 75mA
peak voltage between any two electrodes or between any electrode and heater 
= 350V

I'm thinking that it's a hydrogen type.  If it was mercury, wouldn't there 
be a bit of metallic mercury loose within the tube which vaporizes during 
operation?  There's no loose material inside this tube, so, hydrogen?
John