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Voltage Dual Pentode ·Pentode-Pentode

4HS8

Twin pentode designed for television AGC, sync-separator, sync-clipper, and noise-gating service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
-
Socket code
B9A
Base pins
9
Nominal heater
4.2 V / 450 mA

Description

Twin pentode used in television AGC, sync-separator, sync-clipper, and noise-gating service.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B9A
Base pins
9
Nominal heater voltage
4.2 V
Nominal heater current
450 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

2 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances
Max plate voltage
300 V
Max screen voltage
150 V
Max plate dissipation
1.1 W
Max screen dissipation
0.75 W
Max cathode current
12 mA

Representative electrical row for two identical sharp-cutoff pentode units; used in AGC, sync, limiting and clipping circuits.

Section 2

Pentode

X-ray radiationInterelectrode capacitances
Max plate voltage
300 V
Max screen voltage
150 V
Max plate dissipation
1.1 W
Max screen dissipation
0.75 W
Max cathode current
12 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

Pentode

Characteristic

  • Grid1Transconductance

    1100 uS

    Section1

SECTION 2

Pentode

Characteristic

  • Grid3 Transconductance

    450 uS

    Section2

Data set 02

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Pentode

Capacitance

  • GRID #

    3.6 pF

    Capacitances | GRID #3 (EACH SECTION) TO ALL 3.6 pf

  • PLATE (EACH SECTION) TO ALL

    3 pF

    Capacitances | PLATE (EACH SECTION) TO ALL 3.0 pf

  • GRID #

    0.017 pF

    Capacitances | GRID #3 (SECTION 1) TO GRID #3 (SECTION 2). MAX. 0.017 pf

Other

  • HEATER WARM—UP TIMER Z

    1 s

    Average Characteristics | HEATER WARM—UP TIMER Z1 SECONDS

  • SCREEN DISSIPATION

    0.75 W

    Maximum Ratings | SCREEN DISSIPATION 0.75 WATT

  • GRID #i CIRCUIT RESISTANCE O

    5 Mohm

    Maximum Ratings | GRID #i CIRCUIT RESISTANCE O.5 MEGOHM

  • SCREEN VOLTAGE

    67.5 V

    Average Characteristics | SCREEN VOLTAGE 67.5 67.5 VOLTS

  • SCREEN CURRENT

    4.4 mA

    Average Characteristics | SCREEN CURRENT 7.O 4.4 MA.

  • CATHODE CURRENT

    5 mA

    Average Characteristics | CATHODE CURRENT 7.T H.5 MA.

Data set 03

1971 RCA HB3 Binder 4 of 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Typical plate voltage

    250 V

    AGC;SyncLimiter

  • Typical grid 1 voltage

    -11 V

    AGC;SyncLimiter

  • Typical plate current

    5 mA

    AGC;SyncLimiter

  • Typical transconductance

    1800 uS

    AGC;SyncLimiter

Characteristic

  • Heater warm-up time

    11 s

    ControlledWarmUp

Data set 04

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Heater Voltage (ac/dc) 3.5 4.2

    6.3 V

    Published in approved 4HS8 target entry; Section1

  • Heater Current 0.6 0.45

    300 mA

    Published in approved 4HS8 target entry; Section1

  • Heater Warm-up Time (Average) 11

    11 seconds

    Published in approved 4HS8 target entry; Section1

  • Plate Voltage (Each Unit)

    300 V

    Published in approved 4HS8 target entry; Section1

  • Peak positive value

    50 V

    Published in approved 4HS8 target entry; Section1

  • DC negative value

    50 V

    Published in approved 4HS8 target entry; Section1

  • DC positive value

    3 V

    Published in approved 4HS8 target entry; Section1

  • Grid-No.2 (Screen-Grid) Voltage

    150 V

    Published in approved 4HS8 target entry; Section1

  • Grid-No.l (Control-Grid) Voltage, Negative-bias value

    50 V

    Published in approved 4HS8 target entry; Section1

  • Cathode Current

    12 mA

    Published in approved 4HS8 target entry; Section1

  • Plate Dissipation (Each Unit)

    1.1 W

    Published in approved 4HS8 target entry; Section1

  • Grid-No. 2 Input

    0.75 W

    Published in approved 4HS8 target entry; Section1

  • 67.5

    67.5 V

    Published in approved 4HS8 target entry; Section1

  • Plate Current (Each Unit)

    2 mA

    Published in approved 4HS8 target entry; Section1

  • Grid-No.2 Current 7

    4.4 mA

    Published in approved 4HS8 target entry; Section1

  • Cathode Current 7.1

    8.5 mA

    Published in approved 4HS8 target entry; Section1

  • Grid-No.S-Circuit Resistance (Each Unit)

    0.5 MΩ

    Published in approved 4HS8 target entry; Section1

  • Grid-No.l-Circuit Resistance

    0.5 MΩ

    Published in approved 4HS8 target entry; Section1

  • Peak Plate Voltage*

    5500 V

    Published in approved 4HS8 target entry; Section1

  • Plate Dissipation

    35 W

    Published in approved 4HS8 target entry; Section1

  • Peak Plate Current

    325 mA

    Published in approved 4HS8 target entry; Section1

Capacitance

  • Grid No.3 to Plate (Each Unit)

    2 pF

    Published in approved 4HS8 target entry; Section1

  • Grid No.l to All Other Electrodes

    6 pF

    Published in approved 4HS8 target entry; Section1

  • Grid No.3 (Each Unit) to All Other Electrodes

    3.6 pF

    Published in approved 4HS8 target entry; Section1

Characteristic

  • Plate Voltage 100

    100 V

    Published in approved 4HS8 target entry; Section1

  • Grid-No.3 Voltage 0

    0 V

    Published in approved 4HS8 target entry; Section1

  • Grid-No 2 Voltage 67.5

    67.5 V

    Published in approved 4HS8 target entry; Section1

  • Grid-No.l Voltage

    0 V

    Published in approved 4HS8 target entry; Section1

  • Transconductance, Grid No.l to Plate

    1100 µS

    Published in approved 4HS8 target entry; Section1

  • Plate Current

    2 mA

    Published in approved 4HS8 target entry; Section1

  • Pulse Plate Voltage*

    3500 V

    Published in approved 4HS8 target entry; Section1

  • Grid-Voltage, Negative-bias value +200

    4.4 V

    Published in approved 4HS8 target entry; Section1

  • Peak Plate Current

    300 mA

    Published in approved 4HS8 target entry; Section1

  • Plate Resistance (Approx.)

    4600 Ω

    Published in approved 4HS8 target entry; Section1

  • Grid Voltage (Approx.) for plate current of

    1 mA

    Published in approved 4HS8 target entry; Section1

  • Grid Voltage (Approx.) for plate current of 1 mA

    13 V

    Published in approved 4HS8 target entry; Section1