Power - Pentode (NOT beam) ·Pentode
Power-amplifier pentode using a 6.3 V, 0.3 A heater. Manufacturer handbooks identify it for receiver power-output service rather than small-signal voltage amplification.
38 is listed in the supplied receiving-tube handbook as a power-amplifier pentode. The published heater/filament rating is 6.3 V at 0.3 A.
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
Published ratings and characteristics promoted from the approved datasheet.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Grid-plate capacitance
0.3 pF
Published direct interelectrode capacitance
Undistorted power output
525 mW
Published operating characteristic
Load resistance
8500 ohm
Published operating characteristic
Data set 02
Published operating points and test conditions from this source.
Maximum plate voltage
250 V
Published datasheet rating
Maximum screen voltage
250 V
Published datasheet rating
Plate voltage
250 V
ClassA
Screen voltage
250 V
ClassA
Control-grid bias
25 V
ClassA
Plate current
22 mA
ClassA
Screen current
3.8 mA
ClassA
Load resistance
10000 ohm
ClassA
Power output
2.5 W
ClassA
Plate resistance
100000 ohm
Published datasheet characteristic
Transconductance
1200 µS
Published datasheet characteristic
Amplification factor
120
Published datasheet characteristic
Heater/filament voltage
6.3 V
Published heater/filament rating
Heater/filament current
300 mA
Published heater/filament rating
Input capacitance
3.5 pF
Published capacitance
Output capacitance
7.5 pF
Published capacitance
Grid-to-plate capacitance
0.3 pF
Published capacitance
Data set 03
Published operating points and test conditions from this source.
Heater/filament voltage
6.3 V
Published nominal
Heater/filament current
300 mA
Published nominal
Transconductance
1700 uS
Published characteristic
Data set 04
Published operating points and test conditions from this source.
Heater or filament voltage
6.3 V
Published nominal value
Heater or filament current
300 mA
Published nominal value
Transconductance
1200 µS
Published representative/high operating value
Amplification factor
120
Published representative/high operating value
Plate resistance
100000 ohm
Published representative/high operating value
Audio power output
2.5 W
SingleTube; 250 V plate
Load resistance
10000 ohm
SingleTube; 250 V plate
Data set 05
Published operating points and test conditions from this source.
Maximum plate voltage
250 V
Published handbook rating
Maximum screen voltage
250 V
Published handbook rating
Plate voltage
250 V
ClassA
Screen voltage
250 V
ClassA
Control-grid bias
25 V
ClassA
Plate current
22 mA
ClassA
Screen current
3.8 mA
ClassA
Load resistance
10000 ohm
ClassA
Power output
2.5 W
ClassA
Plate resistance
100000 ohm
Published handbook characteristic
Transconductance
1200 µS
Published handbook characteristic
Heater/filament voltage
6.3 V
Published heater/filament rating
Heater/filament current
300 mA
Published heater/filament rating
Data set 06
Published operating points and test conditions from this source.
Plate voltage
250 V
ClassA
Screen voltage
250 V
ClassA
Screen current
3.8 mA
ClassA
Plate resistance
100000 ohm
ClassA
Transconductance
1200 uS
ClassA