Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Specialized - Switching Tube ·SparkGapPulseSwitch

R27

Russian uncontrolled spark-gap switching/protection tube for overvoltage protection.

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 0

SparkGapPulseSwitch

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Uncontrolled spark-gap switching device; breakdown/spark voltage 0.35 kV, range 0.31–0.39 kV. Not an ordinary plate-voltage rating.

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

2026 Russian Spark Gap

Published operating points and test conditions from this source.

SECTION 0

SparkGapPulseSwitch

Other

  • Breakdown voltage

    0.31 to 0.39 kV

    Spark-gap breakdown voltage, nominal with source minimum/maximum; not a conventional anode rating