212 audio electron vacuum tube

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4 Piece/Pieces 4pcs in a special carton sending by air (Min. Order)
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Quick Details
Place of Origin:
Liaoning, China (Mainland)
Brand Name:
Model Number:
Triode Transistor
Package Type:
Surface Mount
glass metal
Supply Ability
Supply Ability:
300 Piece/Pieces per Month
Packaging & Delivery
Packaging Details
Outside size 580*580*450(mm) for sending by air
Dalian port
Lead Time :
Delivery time is 1~5 working days once the payment is confirmed


1.ISO9001:2008& CE
2.Audio electron vacuum tube
3.Used in pair for amplifier
4.Exquisite triode
5.Glass metal electron tube


Audio electron vacuum tube ML-212E is an air-cooled triode that may be used as an audo-frequency amplifier or modulator;or as a radio-frequency oscillator or amplifier. Performance data given below are based upon a typical set of conditions. Variations can be expectd with different circuits and tubes. 

General characteristics

Filament                Thoriated Tungsten

Filament voltage: 14V
Filament current: 6A

Average Thermionic Emission        4A

Average Direct Interelectrode Capacitances
Plate-- Grid: 18.8  μμF
Grid----Filament: 14.9  μμF
Plate-----Filament: 8.6 μμF

Average Characteristics at 2000 volts direct plate potential and minus 90 volts grid bias

 Amplification Factor                  16

 Plate Resistance                       1900Ω

Grid to Plate Transconductance      8500μΩ

 Mechanical properties:
Quality: (approximately) 0.8Kg
Installation: vertical or horizontal mounting, if mounting horizontally the plane of the filament , should be vertical.

Cooling: natural cooling





The maximum anode DC voltage:       3000V
Maximum Anode DC Current: 350mA
Maximum anode dissipation power: 275W
Maximum Direct  Grid current                   75mA

Maximum RF Grid current                        5A

Maximum Frequency for the above ratings    1.5MHz

Maximum Plate Voltage for Upper Frequency Limit of 4.5MHz               1000V

Maximum Plate Voltage for Frequencies between 1.5 and 4.5MHz in proportion.

The above are maximum ratings which do not apply simultaneously but depend on the type of service as specified below.

 Class A Audio Amplifier or Modulator

Direct plate voltage                                        1500     1250     V

Grid      bias                                                      -57     -40      V

Grid    Plate Volage                                            170      200   mA

Plate Dissipation                                                 250      250   W

Load Impedance                                               5000     3000 Ω

Undistorted Output                                             50         40    W


Grid Bias Modulator

Direct Plat Voltage                                                      3000     V

Grid Bias                                                                       -260   V

Plate Dissipation                                                              175   W

Load Impedance                                                           8000    Ω

Peak Power Output                                                        200    W


Class B Audio Amplifier or Modulator for balanced  tube circuit

Direct Plate Voltage                                        2000       1500    V

Grid Bias                                                            -105      -75    V

Dierect Plate Current per tube No drive                 40        50    mA

Maximum Drive                                                   300       300   mA

Plate Dissipation                                                  250       250    W

Load Res. Plate-to - Plate                                  8000     5900   Ω

Load Res. Per  Tube                                          2000     1475   Ω

Approx  Maximum Output                                    650     500     W

Recommended Power for Driving Stage                  50       50     W

Class B Radio-Frequeny Amplifier

Direct Plate Voltage                                            2000     1500    V

Direct Plate Current                                              300       300    mA

Plate Dissipation                                                   275       275    W

Grid Bias                                                             -120      -90     V

Approx. Carrier watts Use wth 100% Modulation   200     150    W

Class C Radio-Frequency Oscillator or Power Amplifier- Unmodulated

Diret Plate Voltage                                                2000    1500   V

Direct Plate  Current                                               300       300  mA

Grid Bias                                   -185  to -250      -150 to -200   V

Nominal Power Output                                           400       300  W

Class C Radio- Frequency Amplifier Plate Modulated

Direct Plate Voltage                                                1500    1000 V

Direct Plate Current                                                   300     300 mA

Grid Bias                                                                  -200    -125  V

Maximum Direct Grid Current                                       75       75   W

Nominal Carrier power output                                     300     200  W

for us with 100% modulation