PHOTOCELL
SIMILAR TO 929
The 1P39 Vacuum tube is like the 929 except the 1P39 is
equipped with a non-hygroscopic base which insures a
value of resistance between anode and cathode pins about
10 times higher than conventional bases under adverse
service conditions of high humidity. This cell measures
70x32mm overall and has an octal base with 5 pins fitted.
CURRENT
Again the 1P39 Vacuum tube is also like the 929 except the 1P39
has a maximum dark current of 0.005 UA at 250
Volts and has a non-hygroscopic base which insures a
value of resistance between Anode and Cathode pins about
10 times higher than conventional bases under adverse
service conditions of high humidity.
Electrical Data:
Max anode supply voltage ........... 250V
Cathode current density ............100µA / sq. inch
Average cathode current .............20µA