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17BH3A

Half-wave vacuum rectifier designed for television damper service, explicitly a heater-voltage variant of the corresponding 6BH3A type with controlled warm-up.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 9HP
Socket code: B9A
Base pins: 9
Nominal heater: 17 V / 600 mA

Description

17BH3A — Half-Wave Vacuum Rectifier

A Novar-type heater-cathode diode designed for damper service in horizontal-deflection circuits of television receivers.

Overview

The 17BH3A is a half-wave vacuum rectifier designed specifically for use as a damper tube in the horizontal-deflection circuits of television receivers, particularly black-and-white systems. It is a heater-cathode diode featuring a 17-volt heater and is constructed in a compact Novar envelope.

The 17BH3A belongs to a family of rectifiers that includes the 6BH3A and 22BH3A, sharing identical electrical ratings and construction except for their heater characteristics. It is also closely related to the 17BH3, from which it differs by having a shorter bulb and a base that features an exhaust tip at the bottom. Because of its power-handling role in television deflection circuits, the 17BH3A requires adequate ventilation during operation.

Mechanical Specifications and Construction

The 17BH3A features a Novar T-9 glass envelope with a 9-pin button base (E9-89). This construction includes an exhaust tip located at the bottom of the base. The physical dimensions of the tube are:

Maximum overall height: 3.005 inches
Maximum seated height: 2.625 inches
Maximum diameter: 1.188 inches

The tube requires a standard Novar 9-contact socket for installation.

Heater Characteristics

The 17BH3A is equipped with an indirectly heated cathode. Its heater is designed for series-string or parallel applications with the following ratings:

Heater Voltage (AC or DC): 17 V
Heater Current: 0.600 ± 0.040 A (600 mA)
Average Heater Warm-up Time: 11 seconds

Pinout and Basing Configurations

The 17BH3A utilizes a 9HP basing diagram. However, different technical records document two distinct pinout configurations for this designation. In both configurations, pins 1, 3, 6, and 8 are designated as Internal Connections (IC) and must not be used as circuit tie points.

Pinout Configuration A

In this configuration, the heater is connected to pins 2 and 9, while the cathode is redundant on pins 4 and 5:

Pin 1: Internal Connection (IC)
Pin 2: Heater (H)
Pin 3: Internal Connection (IC)
Pin 4: Cathode (K)
Pin 5: Cathode (K)
Pin 6: Internal Connection (IC)
Pin 7: Plate (P)
Pin 8: Internal Connection (IC)
Pin 9: Heater (H)

Pinout Configuration B

In this alternative configuration, the heater is connected to pins 4 and 5, the plate is redundant on pins 2 and 7, and the cathode is on pin 9:

Pin 1: Internal Connection (IC)
Pin 2: Plate (P)
Pin 3: Internal Connection (IC)
Pin 4: Heater (H)
Pin 5: Heater (H)
Pin 6: Internal Connection (IC)
Pin 7: Plate (P)
Pin 8: Internal Connection (IC)
Pin 9: Cathode (K)

Direct Interelectrode Capacitances

Measured without an external shield, the approximate direct interelectrode capacitances of the 17BH3A are:

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

Damper Service Ratings

The maximum ratings of the 17BH3A are established under the Design-Maximum Rating System. For operation in a standard 525-line, 30-frame television scanning system, the ratings are as follows:

Plate Ratings

Peak Inverse Plate Voltage: 5500 V (The duty cycle of the voltage pulse must not exceed 15% of one horizontal scanning cycle, or a maximum duration of 10 microseconds)
Steady-State Peak Plate Current: 1100 mA
DC / Average Plate Current: Technical specifications list this limit as either 130 mA or 180 mA depending on the operating standard.
Plate Dissipation: 6.5 W

Heater-Cathode Voltage Ratings

Due to the high-voltage pulses encountered in television horizontal-deflection circuits, the heater-cathode insulation is rated for high peak voltages:

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

Technical Summary

The 17BH3A is a Novar-based, half-wave vacuum rectifier designed for television horizontal damper service. Operating with a 17 V, 0.6 A heater, it provides high peak inverse voltage capability (up to 5500 V) and substantial peak current capacity (1100 mA) to handle the demanding flyback pulses of television deflection systems. Its physical construction features a compact T-9 bulb with an exhaust tip on its 9-pin button base. Designers must observe the specific pinout configuration of the socket and ensure adequate ventilation to accommodate its 6.5 W plate dissipation rating.

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: 17 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

9HP - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
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: 6.8 W
Rectifier peak inverse voltage: 5500 V
Rectifier nominal output current: 180 mA
Rectifier peak forward current: 1.1 A
Rectifier forward voltage drop: 32 V
Rectifier max heater-cathode voltage: 5500 V
Rectifier warm-up time: 11 s

Rectifier section; ratings and characteristics retained in parameter rows where not safely promotable. Inherited from explicitly referenced 6BH3A electrical characteristics; heater differs per current sheet.

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

Characteristics

Voltage (AC or DC) ±
6.3 V
PublishedColumn1
E The do component must not a%teed
900 V
The do component must not exceed
100 V
Voltage (AC or DC) ±
0.6 V
PublishedColumn2
respect to cathodes b max
5500 V
respect to cathode ° max
300 V

Other

Average Plate Current max
180 mA
Plate Dissipation max
6.8 W
Heater voltage
17 V
Reference sheet; AC or DC at rated heater current
Heater current
600 mA
Reference sheet nominal current
Warm-up time
11 s
Average
Peak Inverse Plate Voltages max
5500 V
Peak Plate Current max
1100 mA

Capacitance

P to (H, K)
6.5 pF
K to (P,H)
9 pF
Heater to cathode
2.8 pF