SOVIET MINIATURE FLEXIBLE DOUBLE TRIODE - 6N21B.

The tubes are nos and have never been used.

Two tubes in one lot.

Double triode to amplify low frequency voltage. Weight 4.5 g.

6N21B tube parameters:

(each triode)

Filament voltage 6.3V

Anode voltage 300V

Cathode resistance for automatic bias 330 ohms

Filament current 395 ±35mA

Anode current 3.5 ±1.3mA

Anode current difference <1.5mA

Characteristic slope 3.8 ±1.2mA/V

Characteristic slope at Un=5.7V >2.7mA/V

Gain 82 ±18

Leakage current cathode-heater <20 µA

Reverse grid current (Uc=-1.5V) <0.2 µA

Vibration noise voltage <15mV

Input capacitance 2.7±0.75pF

Output capacitance 0.6±0.25pF

Pass-through capacitance <1.4pF

Capacitance between anodes <0.045pF

Cathode-heater capacity <13pF

Operating time >2000h

Purpose of 6N21B pins:

1 cathode 1

2 screen

3 grid 1

4 anode 1

5 heat

6 cathode 2

7 circumcised

8 grid 2

9 anode 2

10 glow

Connection diagram for tube electrodes 6N21B

Bending and soldering of leads closer than 3mm from the body is not allowed to avoid the formation of glass cracks on the cylinder.

Limit parameters of the 6N21B tube:

(each triode)

Filament voltage 5.7..7.0V

Anode voltage 250V

Locked Lamp Anode Voltage

350V

Grid voltage -50V

Maximum power at the anode 1.0 W

Maximum voltage between cathode and heater ±200V

Maximum cathode current

10mA

Maximum resistance in grid circuit 2Mohm

Maximum cylinder temperature +220°C

Temperature range -60..+125°C

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Tracking number is provided.

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