Z77

Miniature RF pentode for Class-A amplification and mixer service, with manufacturer operating data specifically covering suppressor-grid oscillator injection and frequency conversion in receiver front ends.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: B7G
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 300 mA

Description

Miniature 6.3 V indirectly heated RF pentode for Class-A amplification and mixer service, with published pentode- and triode-connected operating data.

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: 6.3 V
Nominal heater current: 300 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

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 300000 Ω
Transconductance: 0.0075 S
Amplification factor: 75
Max plate voltage: 250 V
Max screen voltage: 250 V
Max plate dissipation: 2.5 W
Max screen dissipation: 0.8 W
Max cathode current: 30 mA

Pentode ratings promoted from the printed RATING table. Amplification factor and 30 mA cathode-current limit are published for triode connection; connection-specific values are also 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

Other

Heater-Cathode Peak Voltage Maximum
150 V
Triode Plate Voltage Maximum
250 V
TriodeConnection
Triode Plate+Screen Dissipation Maximum
3.3 W
TriodeConnection
Typical Anode Voltage
250 V
ClassA;PentodeConnection
Typical Screen Voltage
250 V
ClassA;PentodeConnection
Typical Suppressor Voltage
0 V
ClassA;PentodeConnection
Typical Anode Current
10 mA
ClassA;PentodeConnection
Typical Screen Current
2.5 mA
ClassA;PentodeConnection
Typical Grid1 Voltage
-2 V
ClassA;PentodeConnection
Typical Cathode Resistor
160 ohm
ClassA;PentodeConnection
Mixer Anode Voltage
250 V
Mixer;PentodeConnection;SeriesInjectionG3
Mixer Screen Voltage
250 V
Mixer;PentodeConnection;SeriesInjectionG3
Mixer Anode Current
4.5 mA
Mixer;PentodeConnection;SeriesInjectionG3
Mixer Screen Current
1.5 mA
Mixer;PentodeConnection;SeriesInjectionG3
Mixer Cathode Resistor
680 ohm
Mixer;PentodeConnection;SeriesInjectionG3
Oscillator Peak Injection Voltage
4.5 V
Mixer;SeriesInjectionG3

Characteristic

Pentode Plate Resistance
300000 ohm
PentodeConnection;Va=250V;Vg2=250V;Ia=10mA
Pentode Transconductance
0.0075 A/V
PentodeConnection;Va=250V;Vg2=250V;Ia=10mA
Triode Amplification Factor
75
TriodeConnection;Va=250V;Vg1=-2V
Triode Plate Resistance
10000 ohm
TriodeConnection;Va=250V;Vg1=-2V
Triode Transconductance
0.0075 A/V
TriodeConnection;Va=250V;Vg1=-2V
Conversion Transconductance
0.0027 A/V
Mixer;PentodeConnection;SeriesInjectionG3
Grid-Cathode Input Resistance at 45MHz
9000 ohm
Frequency=45MHz
Equivalent Noise Resistance Referred to Grid1
1000 ohm

Capacitance

Grid1-All Capacitance
7.4 pF
Anode-All Capacitance
3.1 pF
Anode-Grid1 Capacitance
0.009 pF