HD23

Battery double-diode triode combining two signal-rectifying diode systems with a high-magnification triode for subsequent low-frequency amplification in radio receiver detector and audio stages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 3
Base: -
Socket code: -
Base pins: 5
Nominal heater: 2 V / 100 mA

Description

The Marconi HD23 combines two diode sections with a high-magnification triode for signal rectification and subsequent low-frequency amplification.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: 5
Nominal heater voltage: 2 V
Nominal heater current: 100 mA
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

3 physical sections, each with unique specifications.

Section 1

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Marconi HD23 first detector diode of a battery-operated double-diode triode. This physical diode is dedicated to signal rectification when connected to pin 5, as recommended by the manufacturer. The HD23 uses a 2 V, 0.1 A directly heated filament and a five-pin base.

Section 2

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Marconi HD23 second physical diode section for receiver detection/rectification alongside the other diode and a low-frequency amplifier triode. Numerical diode absolute limiting values are not confirmed by the supplied manufacturer sheet.

Section 3

Triode

X-ray radiationInterelectrode capacitances

Max plate voltage: 150 V

Marconi HD23 directly heated triode for receiver AF amplification, with 2 V 0.1 A filament shared with two diode sections. Manufacturer gives typical 120 V and 150 V HT supply operating points, resistive anode loads of 50 kΩ or 250 kΩ, and stage gains approximately 22–28. Stage gain is circuit-dependent and must not be treated as intrinsic amplification factor; transformer coupling can use approximately -1.5 V grid bias.

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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Diode

Application

Diode Function
Signal rectification

Construction

Construction
Diode section

SECTION 2

Diode

Application

Diode Function
Auxiliary diode

Construction

Construction
Diode section

SECTION 3

Triode

Characteristic

Filament Voltage
2 V
Maximum/Published Anode Voltage
150 V
Typical Anode Current
1.5 mA
Typical Voltage Gain
22
Grid Bias for Transformer Coupling
-1.5 V

Capacitance

Grid-Cathode Capacitance
2.75 pF
Grid-Anode Capacitance
2.5 pF
Anode-Cathode Capacitance
10 pF