Power - Pentode (NOT beam) ·Pentode
Rugged long-life Telefunken power pentode designed for high-current service, including approximately 30 W push-pull Class-B operation. Its professional construction emphasizes durability and sustained high-power output.
The Telefunken E235L is a rugged long-life power pentode for high-current service, including 30 W push-pull Class B operation.
International Octal
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
Power pentode.
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.
Plate Voltage
100 V
Screen Voltage
100 V
Plate Current
100 mA
Transconductance
14000 uS
Guaranteed Life
10000 h
Average of 100 tubes
Power Output
30 W
ClassB; PushPull; TwoTubes; PlateVoltage=250V; ScreenVoltage=170V
Data set 02
Published operating points and test conditions from this source.
Typical Plate Voltage
100 V
PentodeConnection
Typical Screen Voltage
100 V
PentodeConnection
Typical Plate Current
100 mA
PentodeConnection
Data set 03
Published operating points and test conditions from this source.
Heater voltage Vs
6.3 V
Heating
Heater current It
1.2 A
Heating
Anode current I
100 mA
Heating
Mutual conductance S
14 mA
Heating
Output power. Class B (two tubes) W,
30 W
Heating
Heater current If
1.12 A to 1.28 A
Characteristics
Anode voltage Vao max
650 V
Limiting Values
Anode dissipation Wa max
15 W
Limiting Values
Anode + grid No.2 dissipation Wa+g2 max
2 W
Limiting Values
Grid No.2 voltage Vgzo max
2 V
Limiting Values
Grid No.2 dissipation Wg2 max
2 W
Limiting Values
Grid No.1 resistor Rgl max
1 MΩ
Limiting Values
Cathode current I max
220 mA
Limiting Values
Cathode peak current Iy max
1.2 A
Limiting Values
cathode negative Vis(kneg) max
200 V
Limiting Values
Heater voltage: The average heater value should be
6.3 V
Limiting Values
Grid No.2 current mA
2 mA
Operating Characteristics
Maximum plate voltage
650 V
Promoted published datasheet value
Maximum screen voltage
650 V
Promoted published datasheet value
Maximum plate dissipation
15 W
Promoted published datasheet value
Maximum screen dissipation
16 W
Promoted published datasheet value
Anode voltage Vy
100 A
Characteristics
Grid No.2 voltage Vgz
2 A
Characteristics
Cathode resistor Ry
75 Ω
Characteristics
Anode current I
85 to 118 mA
Characteristics
Grid No.2 current Ig2
4 to 6.5 mA
Characteristics
Mutual conductance S
11.5 to 16.5 mA
Characteristics
Cut off voltage —Vgl
35 A
Characteristics
Ancde current I,
0.1 mA
Characteristics
Negative grid current —Igl max
1 uA
Characteristics
Anode voltage Va
100 A
Characteristics
Cathode resistor Ry
85 Ω
Characteristics
Anode current Iy
100 mA
Characteristics
Internal resistance Ri
0.35 kΩ
Characteristics
Grid No.1 and other electrodes Ripg min
1 MΩ
Characteristics
Plate resistance
5 Ω
Promoted published datasheet value
Transconductance
14000 µS
Promoted published datasheet value
Amplification factor
5.6
Promoted published datasheet value
cathode and heater ca/g2g3kf
8 to 10 pF
Capacitances
cathode and heater Cc
16.5 to 19.5 pF
Capacitances
Anode to grid No.1 Cagl max
1 pF
Capacitances