1LE3

Small Signal Triode — DHT — Loctal

RCA

Known Equivalents & Substitutes

VT239

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Maximum Plate Voltage110V

Typical Operating

Anode Voltage (typical)Plate Voltage (typical)90V

Grid 1 Bias VoltageGrid Voltage0V

Anode CurrentPlate Current4.5mA

Anode ResistancePlate Resistance11,200Ω

TransconductanceTransconductance1.3mA/V

Amplification Factor (μ)Amplification Factor14.5—

Heater

Heater VoltageFilament Voltage1.4V

Heater CurrentFilament Current0.05A

Notes

RCA Tube Department data, October 15, 1947. Lock-in 8-pin base (Loctal), basing designation 4AA. Glass T-9 bulb.
Directly-heated filament type. Filament voltage 1.4V DC, filament current 0.05A.
Pin 5 is internal connection — do not use. Pin 3 and Pin 4 are no connection.
Direct interelectrode capacitances (triode unit, with external shield connected to negative filament terminal): grid-to-plate 1.7 pF, grid-to-cathode 1.7 pF, plate-to-cathode 3.0 pF.
Maximum plate voltage 110V.
TDSL lists VT239 as close or identical substitute.
Two operating conditions: (1) Va=90V, Vg=0V, mu=14.5, ra=11200 ohms, gm=1300 umhos, Ia=4.5 mA; (2) Va=90V, Vg=-3V, mu=14.5, ra=19000 ohms, gm=760 umhos, Ia=1.4 mA.
NOTE: Despite user expectation of a damper/rectifier type, the RCA datasheet clearly identifies this as a MEDIUM-MU TRIODE for amplifier service.

Pin Layout — Loctal

1Filament (+)

2Plate

3No Connection

4

References