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39
Remote Cutoff Pentode

EIA Base & Outline

EIA Base: 5FEIA Bulb: 12-01
Source ........................................ RCA R-10 - 1932

39
Remote Cutoff Pentode

EIA Base: 5FEIA Bulb: 12-6

Substitute Data

Preferred Substitutes ......................... 44
Source ........................................ RCA RC-13 - 1937

Application

Source ........................................ RCA R-10 - 1932
The '39 is a super-control pentode recommended for use primarily as a radio-frequency amplifier, intermediate-frequency amplifier and superheterodyne first detector in automobile receivers and in sets operated from d-c power lines. It has a heater-cathode which is designed for d-c operation. This feature together with that of general freedom from microphonic and battery circuit disturbances makes the '39 well suited to mobile service and other applications where complete d-c operation is desirable. The '39 is very effective in reducing cross-modulation and modulation-distortion over the usual range of signal voltages without the use of antenna potentiometers or auxiliary volume control switches. This super-control characteristic makes the tube uniquely adaptable to r-f and i-f stages of receivers employing automatic volume control.

The use of a suppressor is an important feature of the '39 because it permits variation in tube structure so as to obtain a high plate resistance without impairing other desired characteristics. In comparison with the usual type of screen grid tube operated under similar conditiona, the '39 has a much higher plate resistance and a considerably increased range of voltage swing. Furthermore, a high value of mutual conductance is maintained.

The suppressor is connected inside the tube to the cathode. During operation of the tube, the suppressor eliminates the secondary emission effects which limit the voltage swing permissible in the usual screen grid tube at low plate voltage, that is, at a plate voltage approximately equal to thc screen voltage. The suppressor in the '39, therefore, makes possible the efficient operation of this tube at a relatively low plate voltage. This may greater than, equal to, or slightly less than the recommended screen voltage.

Mechanical Data

Source ........................................ RCA R-10 - 1932
Bulb .......................................... S-12
Base Type ..................................... Small 5-Pin
EIA Outline ................................... 12-01
EIA Base ...................................... 5F
Top Cap ....................................... Small Metal
Mounting Position ............................. Any

Source ........................................ RCA RC-13 - 1937
Bulb .......................................... ST-12
EIA Outline ................................... 12-6

Electrical Data

Source ........................................ RCA R-10 - 1932
Heater Voltage ................................ 6.3 DC V
Heater Current ................................ 0.3 A

Source ........................................ RCA RC-13 - 1937
Heater Voltage ................................ 6.3 V
Heater Current ................................ 0.3 A

Direct Interelectrode Capacitances (approx)

Pentode
Source ........................................ RCA R-10 - 1932
Input ......................................... 4.0 pf
Output ........................................ 10.0 pf
Grid to Plate ................................. 0.007 pf

Pentode
Source ........................................ RCA RC-13 - 1937
Input ......................................... 3.5 pf
Output ........................................ 10.0 pf
Grid to Plate ................................. 0.007 pf

Maximum Ratings (Design Center Values)

Pentode
Source ........................................ RCA R-10 - 1932
Plate Voltage ................................. 180 V
Grid No. 2 Voltage ............................ 90 V

Pentode
Source ........................................ RCA RC-13 - 1937
Plate Voltage ................................. 250 V
Grid No. 2 Voltage ............................ 90 V

Characteristics and Typical Operation

Class A Amplifier
Source ........................................ RCA R-10 - 1932
Plate Voltage ................................. 90 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 360
Plate Resistance (approx) ..................... 375K Ω
Transconductance .............................. 960 µMho
Plate Current ................................. 4.4 mA
Grid No. 2 Current ............................ 1.3 mA

Class A Amplifier
Source ........................................ RCA R-10 - 1932
Plate Voltage ................................. 135 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 530
Plate Resistance (approx) ..................... 540K Ω
Transconductance .............................. 980 µMho
Plate Current ................................. 4.4 mA
Grid No. 2 Current ............................ 1.2 mA

Class A Amplifier
Source ........................................ RCA R-10 - 1932
Plate Voltage ................................. 180 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 750
Plate Resistance (approx) ..................... 750K Ω
Transconductance .............................. 1000 µMho
Plate Current ................................. 4.5 mA
Grid No. 2 Current ............................ 1.2 mA

Class A Amplifier
Source ........................................ RCA RC-13 - 1937
Plate Voltage ................................. 90 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 360
Plate Resistance (approx) ..................... 375K Ω
Transconductance .............................. 960 µMho
Plate Current ................................. 5.6 mA
Grid No. 2 Current ............................ 1.6 mA

Class A Amplifier
Source ........................................ RCA RC-13 - 1937
Plate Voltage ................................. 180 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 750
Plate Resistance (approx) ..................... 750K Ω
Transconductance .............................. 1000 µMho
Plate Current ................................. 5.8 mA
Grid No. 2 Current ............................ 1.4 mA

Class A Amplifier
Source ........................................ RCA RC-13 - 1937
Plate Voltage ................................. 250 V
Grid No. 2 Voltage ............................ 90 V
Grid No. 1 Voltage ............................ -3 V
Amplification Factor .......................... 1050
Plate Resistance (approx) ..................... 1M Ω
Transconductance .............................. 1050 µMho
Plate Current ................................. 5.8 mA
Grid No. 2 Current ............................ 1.4 mA

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Sat, 10 Dec 2022 02:39:54 -0700