NJ7P SQL Tube Database Query

Note: Please do not link down into my pages. I change this directory structure often and your links will not work correctly.

3A4
Power Amplifier Pentode

EIA Base & Outline

Substitute Data

Substitutes ................................... 3Q4 3W4
Source ........................................ ARRL HB - 1947

Application

Source ........................................ ARRL HB - 1947
Seven-pin miniature type having coated filament used as rf power amplifier in light-weight, compact, portable, low-power, battery-operated equipment.

Source ........................................ ARRL HB - 1947
May be used at full input up to 10 MHz. Class C CCS plate dissipation, 2 watts. Requires miniature 7-contact socket and may be operated in any position.

Mechanical Data

Source ........................................ ARRL HB - 1947
EIA Outline ................................... 5-2
EIA Base ...................................... 7BB

Electrical Data

Source ........................................ ARRL HB - 1947
Heater Voltage ................................ 1.4/2.8 DC V
Heater Current ................................ 0.2/0.1 A

Direct Interelectrode Capacitances (approx)

Pentode
Source ........................................ ARRL HB - 1947
Input ......................................... 4.8 pf
Output ........................................ 4.2 pf
Grid to Plate ................................. 0.34 pf

Maximum Ratings (Design Center Values)

Pentode
Source ........................................ ARRL HB - 1947
Plate Voltage ................................. 150 V
Grid No. 2 Voltage ............................ 135 V
Plate Dissipation ............................. 2 W
Grid No. 2 Dissipation ........................ 0.9 W

Characteristics and Typical Operation

Class A Amplifier
Source ........................................ ARRL HB - 1947
Plate Voltage ................................. 135 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -7.5 V
Plate Resistance (approx) ..................... 90K Ω
Transconductance .............................. 1900 µ
Plate Current ................................. 14.9 mA
Grid No. 2 Current ............................ 2.6 mA
Load Resistance ............................... 8K Ω
Power Output (approx) ......................... 0.6 W

Class A Amplifier
Source ........................................ ARRL HB - 1947
Plate Voltage ................................. 150 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -8.4 V
Plate Resistance (approx) ..................... 100K Ω
Transconductance .............................. 1900 µ
Plate Current ................................. 14.1 mA
Grid No. 2 Current ............................ 2.2 mA
Load Resistance ............................... 8K Ω
Power Output (approx) ......................... 0.7 W

Class C Amplifier
Source ........................................ ARRL HB - 1947
Plate Voltage ................................. 150 V
Grid No. 2 Voltage ............................ 135 V
Grid No. 1 Voltage ............................ -26 V
Grid No. 1 Current ............................ 0.13 mA
Plate Current ................................. 18.3 mA
Grid No. 2 Current ............................ 6.5 mA
Power Output (approx) ......................... 1.2 W

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

Wed, 29 Mar 2023 06:18:57 -0700