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19DQ3

Half-wave vacuum rectifier used as a damper diode in television horizontal-deflection circuits, supplied as a heater variant of its corresponding parent type.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 12FX
Socket code: B12C
Base pins: 12
Nominal heater: 19 V / 600 mA

Description

19DQ3 — Duodecar Half-Wave Vacuum Rectifier

The 19DQ3 (also designated as 19CG3/19DQ3) is a duodecar half-wave vacuum rectifier designed specifically for service as a damper diode in the horizontal-deflection circuits of both color and black-and-white television receivers. Structurally and electrically, the 19DQ3 is identical to the 6CG3, with the sole exception of its heater ratings, which are tailored for series-string heater chains.

Construction, Heater, and Pinout

The 19DQ3 is constructed in a duodecar glass envelope conforming to Outlines section 8G and requires a standard duodecar 12-contact socket for operation. The tube features a 12FX pinout arrangement, which includes several internal connections that must not be used for external circuit tie points, as well as un-connected pins.

Pin Connection Diagram (12FX)

The 12-pin base configuration is arranged as follows:

Pin Number	Connection	Description
1	IC	Internal Connection (Do Not Use)
2	NC	No Connection
3	NC	No Connection
4	H	Heater
5	IC	Internal Connection (Do Not Use)
6	K	Cathode
7	IC	Internal Connection (Do Not Use)
8	IC	Internal Connection (Do Not Use)
9	IC	Internal Connection (Do Not Use)
10	P	Plate
11	NC	No Connection
12	H	Heater

Heater Characteristics

The heater is designed for series or parallel operation with a controlled warm-up time to ensure reliable integration into television receiver power systems.

Heater Voltage (AC/DC): 19 V
Heater Current: 0.6 A
Heater Warm-up Time: 11 seconds
Calculated Heater Power: 11.4 W (calculated from a nominal heater voltage of 19 V and a heater current of 0.6 A)

Electrical Characteristics and Voltage Drop

The 19DQ3 exhibits low internal resistance, which is critical for minimizing power losses in high-efficiency damper service. The instantaneous electrical characteristics are documented under two distinct sets of conditions:

Standard/Family Characteristics: A tube voltage drop of 25 V is typical at an instantaneous plate current of 700 mA.
Alternative/6CG3-Specific Characteristics: A lower tube voltage drop of 20 V is specified at an instantaneous plate current of 680 mA.

Maximum Ratings

The 19DQ3 is rated under the Design-Maximum system for damper service in 525-line, 30-frame television systems. Because the 19DQ3 is identical to the 6CG3 except for its heater, two sets of design-maximum ratings are relevant: the standard family ratings (shared with types 6CG3, 6BW3, 6DQ3, 19CG3/19DQ3, and 25CG3) and the alternative 6CG3-specific ratings.

Design-Maximum Ratings Comparison

Parameter	Standard/Family Ratings	Alternative/6CG3-Specific Ratings
Peak Inverse Plate Voltage	5000 V	5000 V
Peak Plate Current	2100 mA	1500 mA
Average Plate Current	350 mA	350 mA
Plate Dissipation	6.5 W	11 W
Maximum Bulb Temperature (Hottest Point)	—	220 °C
Heater-Cathode Voltage (Peak)	+300 V, -5000 V	+300 V, -5600 V
Heater-Cathode Voltage (Average)	+100 V, -900 V	+100 V, -900 V

The maximum peak inverse plate voltage of 5000 V is rated for a pulse duration not exceeding 15% of a horizontal scanning cycle, or a maximum of 10 microseconds.

Technical Summary

The 19DQ3 is a specialized duodecar half-wave vacuum rectifier designed for damper service in television horizontal-deflection circuits. Operating with a 19 V, 0.6 A heater with an 11-second warm-up time, it provides high-voltage insulation and high peak current capabilities. Depending on the rating system applied, it supports peak inverse plate voltages up to 5000 V, peak plate currents of 1500 to 2100 mA, and plate dissipation limits of 6.5 to 11 W. Its physical construction utilizes a 12-pin duodecar base with a 12FX pinout, ensuring robust isolation for high-voltage pulse operation.

Socket description

Duodecar 12-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 12FX
Socket code: B12C
Base pins: 12
Nominal heater voltage: 19 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

12FX - 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

Rectifier

X-ray radiationInterelectrode capacitances

Max plate dissipation: 6.5 W
Rectifier peak inverse voltage: 5000 V
Rectifier nominal output current: 350 mA
Rectifier peak forward current: 2.1 A
Rectifier forward voltage drop: 25 V
Rectifier warm-up time: 11 s

Damper-service ratings; output-current field uses published average plate current.

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 Warm-up Time —
11 s
Other;PublishedValue1
Heater Warm-up Time —
11 s
Other;PublishedValue2
Peak Inverse Plate Voltage*
5000 V
MaximumRating
Peak Plate Current
2100 mA
MaximumRating
Average Plate Current
300 mA
MaximumRating;PublishedValue1
Average Plate Current
350 mA
MaximumRating;PublishedValue2
Plate Dissipation
6.5 W
MaximumRating
Peak value
-5000 V
MaximumRating
Average value
100 V
MaximumRating;PublishedValue1
Average value
900 V
MaximumRating;PublishedValue2
Tube VoitAge Drop for plate current of
700 mA
MaximumRating;PublishedValue1
Tube VoitAge Drop for plate current of
25 mA
MaximumRating;PublishedValue2
Peak Inverse Plate Voltage
6000 V
Section1;Promoted