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KT33

Output power tetrode designed for receiver audio stages, providing efficient Class-A or Class-AB power amplification from typical receiving-equipment supply voltages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: IO
Base pins: 8
Nominal heater: 25 V / 300 mA

Description

Output tetrode for AC/DC apparatus with supplies below 200 V.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: IO
Base pins: 8
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
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: 0.01 S
Max plate voltage: 200 V
Max screen voltage: 200 V

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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Tetrode

Characteristic

Heater/Filament Voltage
25 V
Heater/Filament Current
300 mA
Transconductance
10000 uS

Other

Maximum/Published Anode Voltage
200 V
Maximum/Published Screen Voltage
200 V
Maximum Published Power Output
5 W
Two-valve service where applicable
Single-Valve Output
5 W
200 V plate/screen

Capacitance

Grid-Anode Capacitance
1.2 pF
Anode-Cathode Capacitance
11.5 pF
Grid-Cathode Capacitance
18.5 pF