U21

High-voltage half-wave rectifier intended for television or mains power-supply service. Its single rectifier section emphasizes high inverse voltage and modest current rather than ordinary full-wave operation.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: IO
Base pins: -
Nominal heater: 2 V / 1.85 A

Description

Rectifier for television or mains power-supply service.

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: -
Nominal heater voltage: 2 V
Nominal heater current: 1.85 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

Rectifier

X-ray radiationInterelectrode capacitances

Rectifier peak inverse voltage: 12500 V
Rectifier nominal output current: 50 mA
Rectifier peak forward current: 55 mA
Rectifier warm-up time: 35 s

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

1960 Mazda

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Characteristics

Maximum RMS anode voltage
4500 V
Approximate warmup delay
35 s