A425

Directly heated high-resistance battery triode for low-current receiving and amplifier service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: A32-1
Socket code: B4
Base pins: 4
Nominal heater: 4 V / 65 mA

Description

Directly heated high-resistance battery triode with two published low-current operating points.

Socket description

European 4-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: A32-1
Socket code: B4
Base pins: 4
Nominal heater voltage: 4 V
Nominal heater current: 65 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

A32-1 - 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

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 20800 Ω
Transconductance: 0.0012 S
Amplification factor: 25
Max plate voltage: 200 V

Promoted only from clearly identified published characteristics/limits; additional operating, capacitance, regulator, gas-tube, and push-pull data retained as section parameters.

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 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
200 V
BatteryValve;OperatingPoint1
Plate current
0.25 mA
BatteryValve;OperatingPoint1
Control-grid voltage
-2.5 V
BatteryValve;OperatingPoint1
Plate voltage
200 V
BatteryValve;OperatingPoint2
Plate current
0.1 mA
BatteryValve;OperatingPoint2
Control-grid voltage
-2.5 V
BatteryValve;OperatingPoint2

Characteristic

Internal resistance
80000 Ω
OperatingPoint1
Internal resistance
250000 Ω
OperatingPoint2
Amplification factor
25
Section1

Capacitance

Grid-to-anode capacitance
3 pF
Section1

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Grid-anode capacitance
3 pF

Other

Plate voltage
200 V
Plate current
0.25 mA
Ra=320kOhm
Plate current
0.1 mA
Ra=1000kOhm