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Power - TV Horizontal Output (sweep) ·BeamPower

17GT5A

Novar beam-power tube designed for television horizontal-deflection amplification, with controlled heater warm-up and high pulse-voltage ratings.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
9NZ
Socket code
B9E
Base pins
9
Nominal heater
16.8 V / 450 mA

Description

17GT5A — Beam Power Pentode

The 17GT5A is a Novar-type beam power pentode designed primarily for use as a horizontal-deflection amplifier in television receivers operating under 525-line, 30-frame systems. It features a compact T-12 envelope construction and is electrically identical to the 6GT5A, differing only in its heater ratings. It is also closely related to the 17GT5, from which it differs by utilizing a shorter bulb and a base configuration that incorporates an exhaust tip at the bottom.

Physical Construction and Basing

The 17GT5A is constructed in a T-12 glass envelope with a Novar Button 9-pin base (designation E9-88), which features an exhaust tip on the base. This design requires a standard Novar 9-contact socket. The physical dimensions of the tube are as follows:

  • Maximum Diameter: 1.562 inches
  • Maximum Seated Height: 2.500 inches
  • Maximum Overall Height: 2.880 inches

The tube utilizes the 9NZ pin connection diagram, which provides the following pinout configuration:

  • Pin 1: Grid No. 2 (Screen Grid)
  • Pin 2: Grid No. 1 (Control Grid)
  • Pin 3: Cathode, Grid No. 3 (Beam Plates)
  • Pin 4: Heater
  • Pin 5: Heater
  • Pin 6: Grid No. 1 (Control Grid)
  • Pin 7: Grid No. 2 (Screen Grid)
  • Pin 8: Internal Connection (IC) — Do not use
  • Pin 9: Plate

Heater and Capacitance Ratings

The 17GT5A is designed for series or parallel heater arrangements, featuring a controlled warm-up time. Its primary heater and interelectrode capacitance characteristics include:

ParameterValue
Heater Voltage (AC/DC)16.8 V
Heater Current0.45 A
Average Heater Warm-up Time11 s
Peak Heater-Cathode Voltage200 max V
Average Heater-Cathode Voltage100 max V

Direct Interelectrode Capacitances

  • Grid No. 1 to Plate: 0.26 pF
  • Grid No. 1 to Cathode, Heater, Grid No. 2, Grid No. 3: 15 pF
  • Plate to Cathode, Heater, Grid No. 2, Grid No. 3: 6.5 pF

Class A1 Operating Characteristics

The 17GT5A can be operated in both triode and pentode configurations. Under Class A1 conditions, the typical operating parameters are defined as follows:

Triode Connection

When Grid No. 2 is connected directly to the plate, the operating parameters are:

  • Plate Voltage: 150 V
  • Grid No. 2 Voltage: 150 V
  • Grid No. 1 Voltage: -22.5 V
  • Amplification Factor (Grid No. 2 to Grid No. 1): 4.4

Pentode Connection

The tube's pentode characteristics are documented under low-voltage and normal-voltage conditions. To prevent exceeding maximum ratings during low-voltage testing, a recurrent waveform method is used to measure peak currents.

ParameterLow Plate VoltageNormal Operation
Plate Voltage60 V250 V
Grid No. 2 Voltage150 V150 V
Grid No. 1 Voltage0 V-22.5 V
Plate Resistance (Approx.)—15,000 Ω
Transconductance—7,100 µmhos
Plate Current390 mA*70 mA
Grid No. 2 Current32 mA*2.1 mA
Grid No. 1 Cutoff Voltage (for Ib = 1 mA)—-42 V

*Measured using a recurrent waveform method.

Horizontal-Deflection Service and Maximum Ratings

In horizontal-deflection amplifier service, the 17GT5A is subject to demanding pulse conditions. The design-maximum ratings must not be exceeded under any operating conditions:

  • DC Plate Supply Voltage: 770 V
  • Peak Positive-Pulse Plate Voltage: 6,500 V (Pulse duration must not exceed 15% of a horizontal scanning cycle, or 10 µs)
  • Peak Negative-Pulse Plate Voltage: 1,500 V
  • DC Grid No. 2 Voltage: 220 V
  • DC Grid No. 1 Voltage: -55 V
  • Peak Negative-Pulse Grid No. 1 Voltage: 330 V
  • Peak Cathode Current: 550 mA
  • Average Cathode Current: 175 mA
  • Plate Dissipation: 17.5 W
  • Grid No. 2 Input: 3.5 W
  • Maximum Bulb Temperature (at hottest point): 240 °C

Circuit Design Constraints

When utilizing grid-resistor-bias operation, the maximum allowable Grid No. 1-circuit resistance is 1.0 MΩ. To prevent thermal runaway or damage to the tube, a bias resistor or other protective means must be incorporated to safeguard the device in the event that excitation is lost. For average characteristic curves, the behavior of this tube corresponds to that of type 6GW6.

Socket description

Novar 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
9NZ
Socket code
B9E
Base pins
9
Nominal heater voltage
16.8 V
Nominal heater current
450 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

9NZ - 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

Beam Power

X-ray radiationInterelectrode capacitances
Plate resistance
15000 Ω
Transconductance
0.0071 S
Amplification factor
4.4
Max plate voltage
650 V
Max screen voltage
220 V
Max plate dissipation
17.5 W
Max cathode current
550 mA

Promoted from published ratings/characteristics where directly applicable; additional published values retained in TUBE_SECTION_PARAMETER.

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

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • Oscillator Voltage

    4.5 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Current

    12 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Transconductance

    3500 µS

    Published in approved 17GT5A target datasheet entry; Section1

  • 6.3

    16.8 V

    Published in approved 17GT5A target datasheet entry; Section1

  • 1.2

    450 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Heater Warm-up Time (Average)

    11 seconds

    Published in approved 17GT5A target datasheet entry; Section1

  • DC Plate Supply Voltage

    770 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Peak Positive-Pulse Plate Voltage#

    6500 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Peak Negative-Pulse Plate Voltage

    1500 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Peak Negative-Pulse Grid-No.l Voltage

    330 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Peak Cathode Current

    550 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Average Cathode Current

    176 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Dissipation*

    17.5 W

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid-No.2 Input

    3.6 W

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid-No.l-Circuit Resistance, for grid-resistor-bias operation*

    1 MΩ

    Published in approved 17GT5A target datasheet entry; Section1

  • # Pulse duration must not exceed 15% of a horizontal scanning cycle (

    10 microseconds

    Published in approved 17GT5A target datasheet entry; Section1

  • Heater Voltage (ac/dc) 6.3

    8.4 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Heater Current 0.6

    450 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Heater Warm-up Time (Average) 11

    11 seconds

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Voltage

    330 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid Voltage, Positive-bias value

    0 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Dissipation

    3 W

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Voltage

    250 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid Voltage

    -10.5 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate Resistance (Approx.)

    5500 Ω

    Published in approved 17GT5A target datasheet entry; Section1

  • Transconductance

    3100 µS

    Published in approved 17GT5A target datasheet entry; Section1

Capacitance

  • Grid No.l to Plate

    0.26 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid No.l to Cathode, Heater, Grid No.2, and Grid No.3

    15 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate to Cathode, Heater, Grid No.2, and Grid No.3

    6.5 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid to Plate 3

    3 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid to Cathode and Heater 3.4

    3.6 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate to Cathode and Heater 0.44

    0.34 pF

    Published in approved 17GT5A target datasheet entry; Section1

  • Plate of Unit No.l to Plate of Unit No.2

    1 pF

    Published in approved 17GT5A target datasheet entry; Section1

Characteristic

  • Plate Voltage 150 60

    250 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid-No.2 (Screen-Grid) Voltage 150 150

    150 V

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid-No.l (Control-Grid) Voltage —22.5 0

    -22.5 V

    Published in approved 17GT5A target datasheet entry; Section1

  • 390 •

    70 mA

    Published in approved 17GT5A target datasheet entry; Section1

  • Grid-No.2 Current 32*

    2.1 mA

    Published in approved 17GT5A target datasheet entry; Section1