1P39

RCA 1P39 high-vacuum S-4 blue-sensitive photoemissive detector, electrically similar to RCA 929 but with a non-hygroscopic base for low leakage under high humidity.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: -

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: -
Nominal heater current: -
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

PhotoemissiveDetector

X-ray radiationInterelectrode capacitances

Max plate voltage: 250 V
Max cathode current: 0.005 mA

RCA 1P39 high-vacuum S-4 blue-sensitive photoemissive detector. Explicit 1P39 maximum dark current 0.005 µA at 250 V (1947 RCA). Otherwise inherits RCA 929 electrical characteristics: max anode supply 250 V DC/peak AC, max average cathode current 5 µA, max cathode current density 25 µA/in², ambient max 75 °C. Peak spectral response 400±50 nm, median luminous sensitivity 45 µA/lm, median radiant sensitivity 0.044 A/W at 400 nm, capacitance ~2.6 pF. 1P39 non-hygroscopic base provides ~10x higher anode-cathode pin insulation under high humidity than 929 conventional base. No heater.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

No source-specific operating conditions are recorded.