Philips designation system

For example: B2046
1st letter heater
A 0.06-0.10 A
B 0.10-0.20 A
C 0.20-0.40 A
D 0.40-0.70 A
E 0.70-1.25 A
F > 1.25 A


next number(s) heater
x heater voltage < 10 V
xx heater voltage >= 10V


last 2 numbers construction
41, 51... tetrode with spacecharge grid
42, 52... tetrode with screen grid
43, 53... power pentode

44, 54... triode with diode or tetrode with diode
45, 55... RF tetrode with variable gain
46, 56... RF pentode
47, 57... RF pentode with variable gain
48, 58... hexode frequency changer
49, 59... hexode with variable gain
xx amplification factor for triodes


last letter (optional)
H
N New, later version

S Series connection allowed

T