Hi peeps, well, in response to another valve related query, this time about 'JAN codes', I thought I would pen a little information nuggett here today. I shall be doing a further more detailed blog entry on military coding history and types soon but for now here's a quick info - bite.
The JAN code is of course the US Military Joint Army Navy coding introduced in 1942 in which the code for a particular valve type comprises of an alphanumeric code, for example VT-114 and additionally a three digit alpha code. I will deal with the former in more detail later, but the alpha code is a manufacturer code. Here is a short listing of the most commonly seen codes with their corresponding manufacturers:-
CHS – Sylvania
CHY – Hytron or CBS-Hytron
CKR – KenRad
CL – GE
CRC – RCA
CRP – Raytheon
There have been multiple USN numbering systems in use over the years.
The initial numbering system was introduced in 1912 with the first of two letters signifying the device manufacturer followed by a sequentially assigned number to indicate valve type.
A replacement system was introduced in 1932 in which the two letter device manufacturer code continued but the numerical part was augmented into a 5 digit number in which the first two designated the valve classification and the successive three the specific type number.
This system was replaced in 1942 using the Joint Army Navy (JAN) system due to a larger range of valve types used in war materiel requiring classification.