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Power - TV Vertical Output ·BeamPower-Triode

21LR8

Combination triode and beam-power tube designed for television vertical-deflection oscillator and amplifier service, with substantial pulse ratings and a 14-watt beam-power section.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 9QT
Socket code: B9E
Base pins: 9
Nominal heater: 21 V / 450 mA

Description

21LR8 is a combined triode and beam-power tube for television deflection service. The supplied RCA manual excerpt was reviewed for heater data, physical sections, maximum ratings, electrical characteristics, capacitances, and stated operating conditions.

Socket description

Novar 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 9QT
Socket code: B9E
Base pins: 9
Nominal heater voltage: 21 V
Nominal heater current: 450 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

9QT - 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

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 16000 Ω
Transconductance: 0.0036 S
Amplification factor: 58
Max plate voltage: 400 V
Max screen voltage: 300 V
Max plate dissipation: 2.5 W
Max cathode current: 105 mA

Reference/equivalence-only source: ratings/characteristics for this section are not reproduced; missing promoted values intentionally not inferred from the referenced 6-series datasheet.

Section 2

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 12000 Ω
Transconductance: 0.0093 S
Amplification factor: 6.5
Max plate voltage: 400 V
Max screen voltage: 300 V
Max plate dissipation: 14 W
Max screen dissipation: 2.75 W
Max cathode current: 260 mA

Reference/equivalence-only source: ratings/characteristics for this section are not reproduced; missing promoted values intentionally not inferred from the referenced 6-series datasheet.

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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater Voltage
21 V
SharedHeater
Heater Current
450 mA
SharedHeater
Heater Warm-up Time
11 s
SharedHeater

SECTION 2

Beam Power

Other

Heater Voltage
21 V
SharedHeater
Heater Current
450 mA
SharedHeater
Heater Warm-up Time
11 s
SharedHeater

Data set 02

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater voltage
21 V
Heater current
450 mA
Heater warm-up time
11 s
ControlledWarmup
Plate voltage
250 V
Triode;ClassA
Grid voltage
-4 V
Triode;ClassA
Plate current
2.3 mA
Triode;ClassA
Maximum DC plate voltage
400 V
VerticalDeflectionOscillator
Peak negative-pulse grid voltage
400 V
VerticalDeflectionOscillator
Peak cathode current
105 mA
VerticalDeflectionOscillator
Average cathode current
30 mA
VerticalDeflectionOscillator
Plate dissipation
2.5 W
Triode
Peak power output
2.5 W
VerticalDeflectionOscillator

Characteristic

Amplification factor
58
Triode
Plate resistance
16000 ohm
Triode
Transconductance
3600 uS
Triode
Cutoff grid voltage at 10 uA plate current
-6.6 V
Triode

Capacitance

Grid-to-plate capacitance
6 pF
Triode
Input capacitance
6.5 pF
Triode
Output capacitance
1.6 pF
Triode

SECTION 2

Beam Power

Other

Plate voltage
135 V
BeamPower;ClassA
Screen voltage
120 V
BeamPower;ClassA
Grid voltage
-10 V
BeamPower;ClassA
Plate current
56 mA
BeamPower;ClassA
Screen current
3 mA
BeamPower;ClassA
Maximum DC plate voltage
400 V
VerticalDeflectionAmplifier
Peak positive-pulse plate voltage
2500 V
VerticalDeflectionAmplifier
Maximum screen voltage
300 V
VerticalDeflectionAmplifier
Peak negative-pulse grid voltage
-250 V
VerticalDeflectionAmplifier
Peak cathode current
260 mA
VerticalDeflectionAmplifier
Average cathode current
75 mA
VerticalDeflectionAmplifier
Plate dissipation
14 W
BeamPower
Screen input
2.75 W
BeamPower

Characteristic

Plate resistance
12000 ohm
BeamPower
Transconductance
9300 uS
BeamPower
Triode-connected amplification factor
6.5
TriodeConnection
Cutoff grid voltage at 1 mA plate current
-26 V
BeamPower
Cutoff grid voltage at 100 uA plate current
-30 V
BeamPower

Capacitance

Grid-to-plate capacitance
0.7 pF
BeamPower
Input capacitance
16 pF
BeamPower
Output capacitance
9 pF
BeamPower
Beam-power grid No.1 to triode plate capacitance
0.12 pF
Coupling
Beam-power plate to triode plate capacitance
0.32 pF
Coupling

Data set 03

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Bias feedback high-voltage regulation
0.47 Mohm
Bias feedback high-voltage regulation 0.47 megohm
DC or pulse shunt high-voltage regulation
10 Mohm
DC or pulse shunt high-voltage regulation 10 megohm
Heater Voltage 6.3 21
31.5 V
Heater Voltage 6.3 21 31.5 volts
Heater Current 1.5 0.45
300 mA
Heater Current 1.5 0.45 0.3 ampere
Heater Warm-up Time . 11
11 s
Heater Warm-up Time . 11 11 seconds
Flate Voltage 400
400 V
Flate Voltage 400 400 volts
Peak Cathode Current 105
260 mA
Peak Cathode Current 105 260 mA.
Average Cathode Current 30
75 mA
Average Cathode Current 30 75 mA
# Pulse duration must not exceed 15% of a horizontal scanning cycle (
10 us
# Pulse duration must not exceed 15% of a horizontal scanning cycle (10 microseconds).
Heater Voltage 6.3 8.1
11.4 V
Heater Voltage 6.3 8.1 11.4 volts
Heater Current 0.6 0.45
315 mA
Heater Current 0.6 0.45 0.315 ampere
Heater Warm-up Time (Average) 11 11
11 s
Heater Warm-up Time (Average) 11 11 11 seconds
Plate Voltage
330 V
Plate Voltage 330 volts
Grid-No.l (Control-Grid) Voltage, Positive-bias value
0 V
Grid-No.l (Control-Grid) Voltage, Positive-bias value 0 volts
For grid-No 2 voltages up to
165 V
For grid-No 2 voltages up to 165 volts 0.65 watt
Maximum plate/supply voltage
330 V
Published section value
Maximum screen-grid voltage
300 V
Published section value
Maximum plate dissipation
3.1 W
Published section value

Characteristic

Plate Voltage 250 45 135
120 V
Plate Voltage 250 45 135 120 volts
Grid-No.l (Control-Grid) Voltage —4 0 —10 —
10 V
Grid-No.l (Control-Grid) Voltage —4 0 —10 —10 volts
Plate Current 2.S 200
51 mA
Plate Current 2.S 200- 51 mA
For plate current of
1 mA
For plate current of 1 mA .
Plate Voltage
125 V
Plate Voltage 125 volts
Plate Current
10 mA
Plate Current 10 mA
Grid-No.l Voltage (Approx.) for plate current of 20 /lA —
3.5 V
Grid-No.l Voltage (Approx.) for plate current of 20 /lA —3.5 volts
Tube Voltage Drop for plate current of
20 mA
Tube Voltage Drop for plate current of 20 mA volts
Plate resistance
200000 ohm
Published section value
Amplification factor
58
Published section value

SECTION 2

Beam Power

Characteristic

Plate Resistance Approx.) 14000
14000 ohm
Plate Resistance Approx.) 14000 14000 ohms
Grid-No.2 Voltage
125 V
Grid-No.2 Voltage 125 volts
Plate Resistance (Approx.)
200000 ohm
Plate Resistance (Approx.) 200000 ohms
Transconductance
13000 uS
Transconductance 13000 /imhos
Grid-No.2 Current
3.4 mA
Grid-No.2 Current 3.4 mA
Plate resistance
200000 ohm
Published section value
Amplification factor
58
Published section value

Other

Grid-No.2 Voltage —
300 V
Grid-No.2 Voltage — 300 volts
Plate Dissipation!: 2.5
14 W
Plate Dissipation!: 2.5 14 watts
Grid-No.2 (Screen-Grid) Supply Voltage
330 V
Grid-No.2 (Screen-Grid) Supply Voltage 330 volts
Plate Dissipation
3.1 W
Plate Dissipation 3.1 watts
For grid-No.2 voltages between 165 and
33 V
For grid-No.2 voltages between 165 and 33 volts See curve page 300
Maximum plate/supply voltage
330 V
Published section value
Maximum screen-grid voltage
300 V
Published section value
Maximum plate dissipation
3.1 W
Published section value