416D

Power Triode — DiscSeal4

Western Electric

Known Equivalents & Substitutes

No known equivalents. If you know of any, use the ⚑ Report Issue button above.

Similar Tubes (Not Drop-In Compatible)

416B

Earlier version in the 416 series — same disc-seal construction but lower ratings

416C

Direct predecessor with same physical format but lower performance specifications

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Max. Plate Voltage400V

Anode Dissipation (max)Max. Plate Dissipation12W

Typical Operating

Anode Voltage (typical)Plate Voltage (typical)250V

Anode CurrentPlate Current50mA

Anode ResistancePlate Resistance3,850Ω

TransconductanceTransconductance65mA/V

Amplification Factor (μ)Amplification Factor

Output

Output PowerOutput Power (at 4 GHz)5W

Capacitances

Grid-to-Plate CapacitanceGrid-Plate Capacitance0.035pF

Input CapacitanceInput Capacitance2.7pF

Output CapacitanceOutput Capacitance0.6pF

Noise / RF

Max Operating FrequencyMax. Operating Frequency4,000MHz

Heater

Heater VoltageHeater Voltage6.3V

Heater CurrentHeater Current1.18A

Notes

Disc-seal (lighthouse) construction with planar electrode geometry minimizes lead inductance for SHF/EHF operation.
Gold-plated body provides low-loss RF grounding contact. Early versions used glass spacers; later production switched to beryllium oxide (BeO) ceramic for better thermal conductivity.
Anode connection via top pin; grid via threaded ring on the body; cathode and heater via the four-pin base.
Requires a coaxial cavity or waveguide mounting structure for microwave operation — not usable in conventional sockets.
Handle with care: BeO ceramic is hazardous if fractured or ground to dust. Do not break or machine the ceramic spacers.
Predecessor tube 416C; the 416D is a selected version with tighter parameter tolerances for higher-frequency operation.

Pin Layout — DiscSeal4

1Heater

2Cathode

3Heater

4Cathode

Ring