7502

Receiver oscillator-converter combining local oscillation and signal mixing for superheterodyne frequency conversion. Its multi-grid structure integrates the front-end frequency-changing functions in one envelope.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 300 mA

Description

The 7502 is a seven pin all glass construction heptode for use as a frequency changer up to 60 Mc/s. The use of a special rugred electrods construction manufactured by means of semi-automatic assembly techinicues contributes to a low catastrophic failure rate. The cathode sleeve is made of a special alloy to inhibit the growth of cathode interface resistance during long periods of operation under cut-off conditions and the pure tungsten heater has been designed to withstand frequent heater switching {sec note) In addition the heater-cathode construction and materials ensure very low levels of leaskage throughout life, The gless base and envelope strain pneatterns are tightly

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: 6.3 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

Heptode

X-ray radiationInterelectrode capacitances

Amplification factor: 1
Max plate voltage: 330 V
Max screen voltage: 110 V
Max cathode current: 15.5 mA

Primary electrical section; identical repeated 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

1954 STC Brimar

Published operating points and test conditions from this source.

SECTION 1

Heptode

Characteristic

as a frequency changer up to 60 Mc/s.
60 MHz
as a frequency changer up to 60 Mc/s.
voltage 120% of nominal value: heater—cathode voltage 240V r.n,s:
240 V
voltage 120% of nominal value: heater—cathode voltage 240V r.n,s:
Voltage (ac or dec) 6.3 volts
6.3 V
Voltage (ac or dec) 6.3 volts
Current O¢3 amps
3 A
Current O¢3 amps
Heater negative with respect to cathode seveeesseess 100 volts
100 V
Heater negative with respect to cathode seveeesseess 100 volts
Heater positive with respect to cathode seveveevssss 100 volts
100 V
Heater positive with respect to cathode seveveevssss 100 volts
Haximum cathode CUrrent e.oeeeesessesrecsssscsssssvesesss 15.5 mA
15.5 mA
Haximum cathode CUrrent e.oeeeesessesrecsssscsssssvesesss 15.5 mA
Meximum screen vOltage seesesessacsscscascecsescscessveoe 110 volts
110 V
Meximum screen vOltage seesesessacsscscascecsescscessveoe 110 volts
Screen current 5.2 75 9.8 mA
9.8 mA
Screen current 5.2 75 9.8 mA
Mutual conductance gm (osc.) 5.5 7425 9.0 mA/V
9 mA
Mutual conductance gm (osc.) 5.5 7425 9.0 mA/V

Other

Maximum anode voltage sseeecsarevacrsssosnssccorcencneseeas 330 volts
330 V
Maximum anode voltage sseeecsarevacrsssosnssccorcencneseeas 330 volts