NJ7P SQL Tube Database Query

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6BR8
Medium-Mu Triode - Sharp-Cutoff Pentode

EIA Base & Outline

Substitute Data

Preferred Substitutes ......................... 6FV8 6JN8
Substitutes ................................... 6BE8 6CL8 6FG7

Application

Miniature type used in color and black-and-white television receiver applications. Especially useful as combined triode oscillator and pentode mixer in vhf television tuners.

Requires miniature 9-contact socket. Except for basing arrangement and grid-1--to-plate capacitance of pentode unit, this is identical to 6U8A.

Mechanical Data

Bulb .......................................... T-6 1/2
Base Type ..................................... Miniature Button 9-Pin
EIA Outline ................................... 6-2
EIA Base ...................................... 9FA
Cathode ....................................... Coated Unipotential
Mounting Position ............................. Any

Electrical Data

Heater Voltage ................................ 6.3 V
Heater Current ................................ 0.45 A
Maximum Heater-Cathode Voltage
Heater Positive with Respect to Cathode
DC Component ............................ 100 V
Total DC and Peak ....................... 200 V
Heater Negative with Respect to Cathode
Total DC and Peak ....................... 200 V

Direct Interelectrode Capacitances (approx)

Pentode
Shielded Unshielded
Input ......................................... 5 5 pf
Output ........................................ 2.6 3.5 pf
Grid to Plate ................................. 0.015 0.008 pf

Triode
Shielded Unshielded
Input ......................................... 2.5 2.5 pf
Output ........................................ 0.4 1.0 pf
Grid to Plate ................................. 1.8 1.8 pf

Maximum Ratings (Design Center Values)

Pentode
Plate Voltage ................................. 300 V
Grid No. 2 Voltage ............................ 300 V
Plate Dissipation ............................. 2.8 W
Grid No. 2 Dissipation ........................ 0.5 W

Triode
Plate Voltage ................................. 300 V
Plate Dissipation ............................. 2.7 W

Characteristics and Typical Operation

Pentode Class A Amplifier
Plate Voltage ................................. 250 V
Grid No. 2 Voltage ............................ 110 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ...................... 68 Ω
Plate Resistance (approx) ..................... 400K Ω
Transconductance .............................. 5200 µ
Plate Current ................................. 10 mA
Grid No. 2 Current ............................ 3.5 mA
Grid No. 1 Voltage for Ib ..................... 10 µa @ -10 V

Triode Class A Amplifier
Plate Voltage ................................. 150 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ...................... 56 Ω
Amplification Factor .......................... 40
Plate Resistance (approx) ..................... 5000 Ω
Transconductance .............................. 8500 µ
Plate Current ................................. 18 mA
Grid No. 1 Voltage for Ib ..................... 10 µa @ -12 V

If you are uncertain about the EIA designator for a particular tube please use the "Index" button to list all the tubes in the database. You can click on the designator for the closest tube.

(c) 1994-2021 by William A. Beech, NJ7P

Fri, 30 Sep 2022 00:23:30 -0700