ZD17

Low-consumption directly heated diode-pentode for battery receiver detector and amplifier service, using a 1.4 V, 50 mA filament to minimize portable-equipment drain.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: B7G
Socket code: B7G
Base pins: 7
Nominal heater: 1.4 V / 50 mA

Description

Miniature 1.4 V directly heated diode-pentode with a shared filament/cathode, intended for low-voltage pentode amplification with a separate diode section.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: B7G
Socket code: B7G
Base pins: 7
Nominal heater voltage: 1.4 V
Nominal heater current: 50 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

B7G - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 600000 Ω
Transconductance: 0.00063 S
Max plate voltage: 90 V
Max screen voltage: 90 V
Max cathode current: 3 mA

Pentode system. Pentode ra/gm are published at Va=Vg2=67.5 V, Vg1=0. Mu=14 is published for triode connection and retained here plus connection-specific parameters.

Section 2

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Diode system sharing the directly heated filament/cathode with the pentode. No separate diode voltage/current maximum is published on the sheet; diode-related capacitances are retained as 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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Filament Current Approximate
50 mA
At nominal 1.4V
Pentode Plate Resistance
600000 ohm
PentodeConnection;Va=67.5V;Vg2=67.5V;Vg1=0
Pentode Transconductance
0.00063 A/V
PentodeConnection;Va=67.5V;Vg2=67.5V;Vg1=0
Triode Amplification Factor
14
TriodeConnection;Va=67.5V;Vg1=0
Triode Plate Resistance
17500 ohm
TriodeConnection;Va=67.5V;Vg1=0
Triode Transconductance
0.0008 A/V
TriodeConnection;Va=67.5V;Vg1=0

Other

Mains Filament Voltage Recommended
1.3 V
MainsSupply
Mains Filament Current Recommended
47.5 mA
MainsSupply
Triode Plate Voltage Maximum
90 V
TriodeConnection
Triode Cathode Current Maximum
3 mA
TriodeConnection
Typical Anode Voltage
45 V
PentodeConnection
Typical Screen Voltage
45 V
PentodeConnection
Typical Voltage Gain
30 ratio
PentodeConnection
Typical Anode Voltage
67.5 V
PentodeConnection
Typical Screen Voltage
67.5 V
PentodeConnection
Typical Voltage Gain
40 ratio
PentodeConnection
Typical Anode Voltage
90 V
PentodeConnection
Typical Screen Voltage
90 V
PentodeConnection
Typical Voltage Gain
50 ratio
PentodeConnection
Grid1-Cathode Resistance
10 Mohm
PentodeConnection

Capacitance

Grid1-All Capacitance
2.2 pF
Anode-All Capacitance
2.4 pF
Grid1-Anode Capacitance
0.2 pF

SECTION 2

Diode

Capacitance

DiodeAnode-Grid1 Capacitance
0.5 pF
DiodeAnode-PentodeAnode Capacitance
0.45 pF
DiodeAnode-Filament Capacitance
1.4 pF