1C1

Battery or receiving-tube frequency converter combining local-oscillator and mixer action for superheterodyne radio service. Its multi-grid structure provides frequency conversion while minimizing component count and, in battery types, filament power.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 1.4 V / 50 mA

Description

Pentagrid frequency changer, directly heated for battery operation.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B7G
Base pins: 7
Nominal heater voltage: 1.4 V
Nominal heater current: 50 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

Heptode

X-ray radiationInterelectrode capacitances

Plate resistance: 600000 Ω
Max plate voltage: 90 V
Max screen voltage: 67.5 V
Max cathode current: 5.5 mA

Mazda 1C1 directly heated pentagrid (heptode) frequency changer for battery superheterodyne receivers; 1.4 V 0.05 A filament, seven-pin B7G base. Manufacturer tentative maximum anode voltage 90 V, screen voltage 67.5 V and maximum mean total cathode current 5.5 mA. Approximate anode impedance 600 kΩ at Va 90 V and screen grids 2/4 at 67.5 V; other operating points yield approximately 0.5–0.8 MΩ. Conversion conductance ~235–300 µmhos across typical conditions is converter-specific, not intrinsic static transconductance. Separate oscillator and signal grid functions exist within one physical heptode.

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

Heptode

Characteristic

Conversion conductance
300 uS
Va=90 V; screen=67.5 V