721B

Hydrogen gas switching tube for roughly 2.8–3.33 GHz pulsed microwave service. Its discharge provides rapid RF-path control in radar systems.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

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

Description

Three-electrode hydrogen-filled gas switching tube for microwave pulse systems, specified over 2800-3330 MHz with recovery-time and ignitor-current ratings.

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

MicrowaveTRSwitch

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Published electrical section from 721B.pdf; identical repeated sections compressed when applicable.

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.

Data set 01

1938 Raytheon

Published operating points and test conditions from this source.

SECTION 1

MicrowaveTRSwitch

Other

Recovery Time (Note 1)
7 µs
Recovery Time (Note 1) 7 usecs (max.)
Peak Dissipation
100 W
Peak Dissipation 100 watts
Average Dissipation
1 W
Average Dissipation 1 watt
Ignitor Open Circuit -800 to
-1000 V
Ignitor Open Circuit -800 to -1000 Vde