Data set 01
1956 Western Electric Tubes
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristic
HeaterOrFilamentVoltage
6.3 V
HeaterOrFilamentCurrent
300 mA
Voltage - Dual Triode (similar high frequency) ·Triode-Triode
2C51
Medium-mu dual triode for versatile electronic service from low frequencies through VHF, including amplifier, mixer, oscillator, multivibrator, and clamp circuits.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 2
- Base
- 8CY
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 6.3 V / 300 mA
Description
Medium-mu dual triode for amplifier, mixer, oscillator, multivibrator, and clamp circuits from low frequency through VHF.
Socket description
Small-button Noval 9-contact
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- 8CY
- Socket code
- B9A
- Base pins
- 9
- Nominal heater voltage
- 6.3 V
- Nominal heater current
- 300 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
8CY - Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
2 physical sections, each with unique specifications.
Section 1
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 6500 Ω
- Transconductance
- 0.0055 S
- Amplification factor
- 35
- Max plate voltage
- 330 V
- Max plate dissipation
- 1.6 W
- Max grid dissipation
- 0.1 W
- Max cathode current
- 16 mA
Two physically identical triode sections with separate cathodes; one representative TUBE_SECTION row is used per the repeated-identical-section rule. Promoted values apply to each section.
Section 2
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 6500 Ω
- Transconductance
- 0.0055 S
- Amplification factor
- 35
- Max plate voltage
- 330 V
- Max plate dissipation
- 1.6 W
- Max cathode current
- 16 mA
Second physical triode restored under current section policy.
Source-dependent data
Operating conditions by source
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 02
195X General Electric Essential Characteristics
Published operating points and test conditions from this source.
SECTION 1
Triode
Capacitance
Input capacitance
2.3 pF
Section1
Output capacitance
1.3 pF
Section1
Grid-to-plate capacitance
1.3 pF
Section1
Other
Plate voltage
150 V
ClassA
Cathode resistor
240 Ω
ClassA
Plate current
8.2 mA
ClassA
Characteristic
Plate resistance
6500 Ω
ClassA
Transconductance
5500 µS
ClassA
Amplification factor
35
ClassA
Data set 03
1961 Tung Sol
Published operating points and test conditions from this source.
SECTION 1
Triode
Capacitance
Grid To Plate Capacitance
1.5 pF
EachSection;WithShield
Input Capacitance
2.38 pF
EachSection;WithShield
Output Capacitance
1.55 pF
EachSection;WithShield
Other
Plate Voltage
150 V
ClassA;EachSection
Characteristic
Plate Current
8.2 mA
ClassA;EachSection
Data set 04
1965 Ericsson Longlife
Published operating points and test conditions from this source.
SECTION 1
Triode
Other
Plate supply voltage
150 V
ClassA;EachSection
Cathode bias resistor
240 Ohm
ClassA;EachSection
Plate current
8.2 mA
ClassA;EachSection
Plate supply voltage
300 V
ClassAB;PushPull;TwoTubes
Load impedance plate-to-plate
40000 Ohm
ClassAB;PushPull;TwoTubes
Maximum signal power output
1 W
ClassAB;PushPull;TwoTubes
Total harmonic distortion
10 %
ClassAB;PushPull;TwoTubes
Heater current maximum
320 mA
Plate current maximum
10 mA
EachSection
Transconductance maximum
6600 uS
EachSection
Characteristics
Transconductance
5500 uS
ClassA;EachSection
Amplification factor
35 ratio
ClassA;EachSection
Plate resistance
6400 Ohm
ClassA;EachSection
Equivalent noise resistance
500 Ohm
EachSection
Input conductance at 100 MHz
130 uS
EachSection
Data set 05
1966 Tung Sol Electronic Tubes 1 of 4
Published operating points and test conditions from this source.
SECTION 1
Triode
Capacitance
Grid-to-plate capacitance
1.3 pF
EachSection
Input capacitance
2.3 pF
EachSection
Output capacitance
1.3 pF
EachSection
Plate-to-plate capacitance
0.038 pF
BetweenSections
Other
Heater-to-cathode voltage maximum
90 V
EachSection
Plate voltage
150 V
ClassA;EachSection
Cathode-bias resistor
240 Ω
ClassA;EachSection
Plate current
8.2 mA
ClassA;EachSection
Application
Amplifier, mixer, oscillator, multivibrator, clamp; low frequency through VHF
Section1
Characteristic
Plate resistance
6500 Ω
EachSection
Transconductance
5500 µS
EachSection
Amplification factor
35
EachSection
Data set 06
196X LM Ericsson
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristics
Heater voltage
6.3 V
Heater current
300 mA
Plate resistance
6400 ohm
Transconductance
5500 uS
Amplification factor
35
Other
Maximum plate voltage
330 V
Maximum plate dissipation
1.6 W
Data set 07
2026 Western Electric 300s
Published operating points and test conditions from this source.
SECTION 1
Triode
Other
GridPlateCapacitance
1.3 pF
Per section; without external shield
Input Capacitance
2.2 pF
Per section; without external shield
Output Capacitance
1 pF
Per section; without external shield
Plate To Plate Capacitance
0.04 pF
Typical; without external shield
MaximumPlateToPlateCapacitance
0.11 pF
Without external shield
Maximum Plate Current
16 mA
Each section
Maximum Heater Cathode Voltage
90 V
Characteristic
Plate Current
8.2 mA
ClassA; EachSection; Plate=150 V; Grid=-2 V
Transconductance
5500 uS
ClassA; EachSection; Plate=150 V
Amplification Factor
35
ClassA; EachSection