QY3125

Thoriated-tungsten directly heated VHF power tetrode designed for RF and modulator service. Its filamentary transmitting construction supports professional high-frequency output.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 5 V / 6.5 A

Description

The Mullard QY3125 is a thoriated-tungsten directly heated VHF power tetrode for RF and modulator service.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 5 V
Nominal heater current: 6.5 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

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

Tetrode

X-ray radiationInterelectrode capacitances

Transconductance: 0.0022 S
Max plate voltage: 3000 V
Max screen voltage: 600 V
Max plate dissipation: 125 W

Published ratings and characteristics promoted semantically from the approved source; repeated identical physical sections compressed where applicable.

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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Tetrode

Other

Operating Frequency Full Ratings
120 MHz
Operating Frequency Reduced Ratings
200 MHz
Power Output
375 W
ClassC,120MHz

Data set 02

1963 Mullard

Published operating points and test conditions from this source.

SECTION 1

Tetrode

Characteristics

Heater/Filament Voltage
5 V
Heater/Filament Current
6.5 A
Transconductance
2200 uS
RepresentativeSpecifiedOperatingPoint
Input Capacitance
10.8 pF
Output Capacitance
3.1 pF
Plate-Grid Capacitance
0.05 pF

Other

Maximum Operating Frequency
200 MHz
FullOrSpecifiedRatings
Maximum Plate Voltage
3000 V
Maximum Screen Voltage
400 V
Maximum Plate Dissipation
125 W
RF Output Power
375 W
RepresentativePublishedOperatingPoint
RF Output Power
300 W
RepresentativePublishedOperatingPoint
Push-Pull Audio Output Power
550 W
RepresentativePublishedOperatingPoint
Plate Voltage
3000 V
ClassC; f<120MHz
Screen Voltage
350 V
ClassC
Plate Current
167 mA
ClassC
RF Output Power
375 W
ClassC
Efficiency
75 percent
ClassC