CRT Question - Old Calculator

I thought '1' was defind as >0 to <2V filament voltage. 0 was reserved strictly for cold cathode vavles/tubes. IOn any case, I find the US valve numberign system very irritating. It tells you almsot nothign abotu the valve. The heater voltage number has incosistnecies (like the use of 7 and 14 to mean 6.3V and 12.6V on a loctal base -- msot fo the time). The last digit is supposed to be something like the number of useful elemenets. But then a 6C4 is a simple triode, so is a 6J5. I was told you count the metal shell in the last case for some odd reason. I've foudn that if I know what hte vlave is, I can find a justification of the number of useful elements, but trying to deduce waht is is fro mthe code is impossible. No, I prefer the Philips (European) code. There are a few mis-assigned numbers in my experience (for some odd reason a few valves with a '70-series' base code were actually Loctals, not subminiatures), but most of the time it's consistent. A lot of the complaints I've heard come from people who don't realise the meaning of soem bits of the code was changed when they went to 3 digts (from 2 digits). For example, with 2 digts on the end, 'G' at the strt means a 5V heater. So a GZ34 is a full-wave vacuum rectifier with a 5V heater on an octal base. But with 3 digits, 'G' at th satrt means 'miscellaneous heater voltage' So a GY501 is, indeed, a half wave rectifier on a B9G (Magnoval) base with, in fact, a 3.15V heater (IIRC). -tony