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Rectifier - Damper Diode ·Rectifier

17BS3A

Novar half-wave vacuum rectifier designed as a damper diode in television horizontal-deflection circuits; heater variant of the corresponding 6-volt type.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
9HP
Socket code
B9A
Base pins
9
Nominal heater
16.8 V / 450 mA

Description

17BS3A — Half-Wave Vacuum Rectifier

The 17BS3A (also designated as 17BS3A/17DW4A) is a Novar-type, heater-cathode half-wave vacuum rectifier. It is designed primarily for service as a damper tube in the horizontal-deflection circuits of television receivers, including both black-and-white and color television systems.

Mechanical Construction and Installation

The 17BS3A is constructed in a T-9 glass envelope with a button 9-pin base (E9-89) and uses the 9HP basing diagram. It requires a standard Novar 9-contact socket (Outlines section 30B).

Physical Dimensions

  • Maximum Diameter: 1.188 inches
  • Maximum Seated Height: 2.625 inches
  • Maximum Overall Height: 3.005 inches

Installation and Ventilation Precautions

As a power-handling tube, the 17BS3A requires adequate ventilation to prevent overheating. The maximum bulb temperature at the hottest point must not exceed 180 °C.

To prevent electrical breakdown, minimize leakage, and reduce the risk of arc-over under high-voltage operation, specific socket precautions must be observed:

  • Terminals 1, 3, 6, and 8 must not be used as tie points.
  • It is highly recommended to remove the socket clips for pins 1, 3, 6, and 8.

Pinout and Connections

The 17BS3A utilizes the 9HP basing arrangement. The connections for this basing diagram present two distinct configurations:

Pinout Configuration A

PinConnection
1Internal Connection (IC) — Do not use as tie point
2Plate (P)
3Internal Connection (IC) — Do not use as tie point
4Heater (H)
5Heater (H)
6Internal Connection (IC) — Do not use as tie point
7Plate (P)
8Internal Connection (IC) — Do not use as tie point
9Cathode (K)

Pinout Configuration B

PinConnection
1Internal Connection (IC) — Do not use as tie point
2Heater (H)
3Internal Connection (IC) — Do not use as tie point
4Cathode (K)
5Heater (H)
6Internal Connection (IC) — Do not use as tie point
7Plate (P)
8Internal Connection (IC) — Do not use as tie point
9Cathode (K)

Heater Characteristics

The 17BS3A features an indirectly heated, coated unipotential cathode. The heater is designed for operation with either AC or DC supply.

Heater ParameterValue
Nominal Heater Voltage16.8 V
Nominal Heater Current0.45 A (or 0.450 ± 0.030 A)
Calculated Heater Power7.56 W (calculated as 16.8 V × 0.45 A)
Average Heater Warm-up Time11 seconds

Electrical Characteristics and Ratings

The tube's ratings are specified under the Design-Maximum system for operation in a 525-line, 30-frame television system. Depending on the specific operating standards, the maximum ratings and typical characteristics are defined as follows:

Maximum Ratings (Design-Maximum Values)

  • Peak Inverse Plate Voltage: 5000 V to 5500 V (The pulse duration must not exceed 15% of a horizontal scanning cycle, equivalent to 10 microseconds)
  • Peak Plate Current: 1100 mA to 1200 mA
  • Average Plate Current: 200 mA
  • Plate Dissipation: 6.0 W to 6.5 W
  • Bulb Temperature (Hottest Point): 180 °C
  • Heater-Cathode Voltage:
    • Peak Value: +300 V (heater positive), and -5000 V to -5500 V (heater negative)
    • Average Value: +100 V (heater positive), and -900 V (heater negative)

Instantaneous Tube Voltage Drop

The internal voltage drop across the tube varies with the instantaneous plate current:

  • 12 V when measured at an instantaneous plate current of 140 mA.
  • 19 V when measured at an instantaneous plate current of 250 mA.

Direct Interelectrode Capacitances

The approximate capacitances of the tube electrodes (measured without an external shield) are:

  • Plate to Cathode and Heater: 6.5 pF
  • Cathode to Plate and Heater: 9 pF
  • Heater to Cathode: 2.8 pF

Related Designations

The 17BS3A is electrically identical to the 6BS3A and 12BS3A/12DW4A except for its heater voltage and current ratings. It is also closely related to the 17BS3, sharing identical electrical characteristics but differing in physical construction; the 17BS3A has a shorter bulb and a base equipped with an exhaust tip at the bottom.

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
9HP
Socket code
B9A
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

Reference-only sheet; parent electrical ratings not reproduced in supplied source.

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

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

  • Heater voltage

    16.8 V

    AC or DC at rated heater current

  • Heater current

    450 mA

    Nominal current

  • Warm-up time

    11 s

    Average

  • Reference parent type

    6BS3A

    Electrical characteristics same except heater

Data set 02

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