Tube Numbering Systems.doc

1st letter

heater indication

0

tubes without filament

A

4 V AC parallel connection

B

180 mA DC

C

200 mA AC/DC series or parallel connection

D

<= 1.4 V DC dry-battery, parallel connection

E

6.3 V AC or carbattery, parallel connection

F

13 V carbattery

G

5V AC parallel connection

H

early: 4V DC battery. later: 150mA AC/DC series connection

I

20V AC/DC parallel connection

K

2 V battery

O

150 mA AC/DC series connection

P

300 mA AC/DC series connection

U

100 mA AC/DC series connection

V

50mA AC/DC series connection

X

600 mA AC/DC series connection

Y

450 mA AC/DC series connection

2nd+next letters

tube systems

A

single detection diode

B

double detection diode

C

small-signal triode

D

power triode

E

small-signal tetrode (or 2nd emmission tube EE1)

F

small-signal pentode

H

hexode or heptode

K

octode

L

power pentode or power tetrode

M

indicator tube

N

thyratron

Q

enneode

W

single gasfilled rectifier diode

X

double gasfilled rectifier diode

Y

single vacuum rectifier diode

Z

double vacuum rectifier diode

digits

socket & order

x

P (some are V) (except U-series (e.g.UBL1), those are octal)

1x

Y8A

2x

W8A, Loctal (except D-series (e.g. DL21), those are octal)

3x

K8A, A08, octal

4x

A8A, B8A, Rimlock