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395A

Small cold-cathode neon thyratron requiring no heater, intended primarily for relay operation and also useful as a trigger tube, relaxation oscillator, and voltage regulator.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: UX4
Base pins: -
Nominal heater: -

Description

The 395A is a small cold-cathode thyratron requiring no heater power and intended primarily for relay operation; it is also suitable as a trigger tube, relaxation oscillator, and voltage regulator.

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: UX4
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

Thyratron

X-ray radiationInterelectrode capacitances

Max plate voltage: 140 V
Max cathode current: 13 mA

Forward/inverse peak anode voltage 140 V; maximum average forward cathode current 13 mA.

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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

Positive anode voltage
140 V
RelayService
Negative anode voltage
-60 V
NoDischargeToPositiveGrid
Peak recurring cathode current
25 mA
AveragedOver1Second
Typical anode supply voltage
130 V
RelayService
Typical grid trigger voltage
20 V
RelayService

Characteristic

Anode voltage drop
75 V
40mA

Data set 02

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

Positive anode voltage maximum
140 V
RelayService
Peak recurring cathode current
35 mA
RelayService
Peak inverse anode current
1 mA
RelayService
Typical anode supply voltage
130 V
RelayService
Typical positive grid bias
70 V
RelayService
Typical grid trigger voltage
20 V
RelayService
Maximum plate voltage
140 V
PromotedValue
Maximum cathode current
35 mA
PromotedValue
Positive Anode Voltage
140 V
PublishedTable
Peak, Recurring (Averaged Over 1 Second)
35 mA
PublishedTable
Peak Inners£ Anode Current
1 mA
PublishedTable
Anode Supply Voltage
130 V
PublishedTable
Grid Circuit Resistance
1 Mohm
PublishedTable

Characteristics

Ionization time
23 us
RelayService
Anode voltage drop
75 V
RelayService
Grid voltage drop
65 V
RelayService
Anode ionization voltage
170 V
RelayService
Grid ionization voltage
75 V
RelayService
Anode Voltage Drop (At Ib = 10. Ma.)
75 V
PublishedTable
Anode Ionization Voltage (At E Q = O)
170 V
PublishedTable
Ido E _+
75 V
PublishedTable
Rg = 0
1 Mohm
PublishedTable

Data set 03

2026 Western Electric 300s

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

ForwardPeakAnodeVoltage
140 V
InversePeakAnodeVoltage
140 V
PeakForwardCathodeCurrent
35 mA
PeakInverseCurrentAnodeOrStarter
1 mA
Ruggedness
1000 G
Centrifuge test

Characteristic

StarterBreakdownVoltage
80 V
Bogey; Min=71 V; Max=84 V
StarterVoltageDrop
65 V
10 mA; Bogey
Anode Voltage Drop
80 V
10 mA; Bogey
RequiredTransferCurrent
10 uA
130 V anode
DeionizationTimeMainGap
2 ms
Bogey
IonizationTimeStarterGap
0.05 ms
Bogey