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Rectifier - Damper Diode ·Rectifier

17DW4A

Novar half-wave vacuum rectifier used as a damper diode in television horizontal-deflection circuits.

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

Description

17DW4A — Half-Wave Vacuum Rectifier and Damper Diode

The 17DW4A is a heater-cathode half-wave vacuum rectifier designed specifically for service as a damper diode in the horizontal-deflection circuits of television receivers. It is utilized in both black-and-white and color television designs. The tube is constructed in a T-9 glass envelope with a 9-pin novar button base and features a 16.8 V heater with a controlled warm-up time.

The 17DW4A is electrically identical to the 6BS3A except for its heater ratings, and is closely associated with the 17BS3A/17DW4A designation.

Construction, Physical Dimensions, and Installation

The 17DW4A features a Novar T-9 glass envelope and uses a 9-pin novar button base (E9-75) with a 9HP basing arrangement.

Physical Dimensions

  • Maximum Diameter: 1.188 inches
  • Maximum Seated Height: 3.030 inches
  • Maximum Overall Height: 3.410 inches
  • Envelope Outline: Section 30B

Installation and Socketing

The tube requires a novar 9-contact socket. Because of the high voltages present in television damper service, specific socketing precautions must be observed:

  • Socket terminals 1, 3, 6, and 8 are connected to internal tube structures (Internal Connection - IC) and must not be used as circuit tie points.
  • It is recommended to remove the socket clips for pins 1, 3, 6, and 8 to reduce the risk of electrical arc-over and minimize leakage currents.
  • Adequate ventilation must be provided in the equipment layout to prevent overheating, as the maximum bulb temperature at the hottest point must not exceed 180 °C.

Pinout and Connections

The 17DW4A uses the 9HP pinout configuration. There are minor variations in documentation regarding Pin 2, which is either designated as an internal connection or as an additional plate connection. The connections, viewed from the underside of the base, are:

PinConnection
Pin 1IC (Internal Connection - do not use as tie point, recommend removing socket clip)
Pin 2IC (Internal Connection) or P (Plate)
Pin 3IC (Internal Connection - do not use as tie point, recommend removing socket clip)
Pin 4H (Heater)
Pin 5H (Heater)
Pin 6IC (Internal Connection - do not use as tie point, recommend removing socket clip)
Pin 7P (Plate)
Pin 8IC (Internal Connection - do not use as tie point, recommend removing socket clip)
Pin 9K (Cathode)

Heater Ratings

The heater is designed for series or parallel operation with a controlled warm-up time:

ParameterValue
Heater Voltage (AC/DC)16.8 V
Heater Current0.45 A (450 mA)
Average Heater Warm-up Time11 s

Electrical Characteristics and Typical Operation

The 17DW4A exhibits a low internal voltage drop under typical instantaneous current loads. The documented typical operating points are:

  • Tube Voltage Drop (Point 1): 19 V at an instantaneous plate current (IbI_b) of 250 mA.
  • Tube Voltage Drop (Point 2): 25 V at an instantaneous plate current (IbI_b) of 350 mA.

Direct Interelectrode Capacitances

The unshielded capacitances of the tube are approximately:

  • Plate to Cathode and Heater: 6.5 pF
  • Cathode to Plate and Heater: 9.0 pF
  • Heater to Cathode: 2.8 pF

Maximum Ratings (Design-Maximum System)

The ratings for the 17DW4A are specified under the Design-Maximum Rating System for operation in a 525-line, 30-frame television system (Damper Service). Depending on the specific application and design standard, the maximum limits are defined as follows:

Rating ParameterValue Range / Limit
Peak Inverse Plate Voltage5500 V (Pulse duration must not exceed 15% of a horizontal scanning cycle, or 10 µs)
Steady State Peak Plate Current1200 mA to 1300 mA
DC / Average Plate Current200 mA to 250 mA
Plate Dissipation6.5 W to 8.5 W
Maximum Bulb Temperature180 °C

Heater-Cathode Voltage Limits

The insulation between the heater and the cathode is designed to withstand high pulse voltages, which is critical in damper service where the cathode is often at a high pulse potential relative to ground:

  • Heater Negative with Respect to Cathode:
    • DC Limit: 900 V
    • Total DC and Peak Limit: 5500 V
  • Heater Positive with Respect to Cathode:
    • DC Limit: 100 V
    • Total DC and Peak Limit: 300 V

Technical Summary

The 17DW4A is a specialized novar-based, half-wave vacuum rectifier designed for television damper service. Operating with a 16.8 V, 450 mA heater, it features high peak inverse voltage capabilities up to 5500 V and can handle peak currents up to 1300 mA. Its construction utilizes a T-9 envelope with a 9HP pinout, requiring careful socketing practices (such as removing unused socket clips) to prevent arc-over under high-voltage pulse 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
9HP
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

9HP - Terminal pinout

Electrical assignments shared by every tube using this base designation.

TerminalSectionConnectionEvidence
PIN1Base Pin—IC

Original chart label IC; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN2Base Pin—P — Plate (Anode)

Original chart label P; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN3Base Pin—IC

Original chart label IC; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN4Base Pin—H — Heater

Original chart label H; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN5Base Pin—H — Heater

Original chart label H; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN6Base Pin—IC

Original chart label IC; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN7Base Pin—P — Plate (Anode)

Original chart label P; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN8Base Pin—IC

Original chart label IC; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

PIN9Base Pin—K — Cathode

Original chart label K; manufacturer verification pending

Unverified

EIA Base Connections printed p133, 9HP

Section ratings

1 physical section, each with unique specifications.

Section 1

Rectifier

X-ray radiationInterelectrode capacitances
Max plate dissipation
6 W
Rectifier peak inverse voltage
5000 V
Rectifier nominal output current
200 mA
Rectifier peak forward current
1.1 A
Rectifier forward voltage drop
12 V
Rectifier warm-up time
11 s

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

Rectifier

Other

  • Heater Voltage (ac/dc) 6-3 12.6

    16.8 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater Current 1-2 0.6

    450 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater Warm-up Time (Average) — 11

    11 seconds

    Published in approved 17DW4A target datasheet entry; Section1

  • Peak Inverse Plate Voltage*

    5000 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Peak Plate Current

    1100 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Average Plate Current

    200 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Peak value -f300 —

    -5000 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Average value +100

    900 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Tube Voltage Drop for plate current of

    140 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Tube Voltage Drop for plate current of 140 mA

    12 V

    Published in approved 17DW4A target datasheet entry; Section1

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

    10 microseconds

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater Voltage (ac/dc) 3.15 4.2

    6.3 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater Current 0.6 0.45

    300 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater Warm-up Time (Average) 11

    11 seconds

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate Voltage (Each Unit)

    300 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Peak positive value

    50 V

    Published in approved 17DW4A target datasheet entry; Section1

  • DC negative value

    50 V

    Published in approved 17DW4A target datasheet entry; Section1

  • DC positive value

    3 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.2 (Screen-Grid) Voltage

    150 V

    Published in approved 17DW4A target datasheet entry; Section1

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

    50 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Cathode Current

    12 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate Dissipation (Each Unit)

    1.1 W

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.2 Input

    0.75 W

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate Voltage (Each Unit) 100

    100 V

    Published in approved 17DW4A target datasheet entry; Section1

Capacitance

  • Plate to Cathode and Heater

    6.5 pF

    Published in approved 17DW4A target datasheet entry; Section1

  • Heater to Cathode z

    8 pF

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid No. 3 to Plate (Each Unit)

    1.9 pF

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid No.l to All Other Electrodes

    6 pF

    Published in approved 17DW4A target datasheet entry; Section1

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

    3.6 pF

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate to All Other Electrodes (Each Unit)

    3 pF

    Published in approved 17DW4A target datasheet entry; Section1

Characteristic

  • Grid-No-3 Voltage (Each Unit) —10

    0 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.2 Voltage 67.6

    67.5 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate Current (Each Unit)

    2.2 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.2 Current 6.5

    3.3 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Cathode Current 6.6

    7.8 mA

    Published in approved 17DW4A target datasheet entry; Section1

  • Plate Voltage 100

    100 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.3 Voltage 0

    0 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.2 Voltage 67.5

    67.5 V

    Published in approved 17DW4A target datasheet entry; Section1

  • Grid-No.3 Transconductance

    180 µS

    Published in approved 17DW4A target datasheet entry; Section1