12SX7GT

12SX7GT has no equivalent designation confirmed by the archive.

General Description

The 12SX7GT is a twin medium-mu triode whose sections are electrically independent except for the common heater. It has a coated unipotential cathode and a glass bulb with a T-9 envelope. The tube is rated for operation at an altitude of 10,000 feet and can be used in any mounting position. It has a short intermediate shell 8-pin octal base, with a JEDEC basing diagram 8BD and a JEDEC outline drawing 9-41.

Ratings

The 12SX7GT heater is rated at 12.6 volts, 0.3 ampere AC or DC, with an operating supply voltage limit of 12.6 volts plus or minus 1.3 volts. The tube is designed for use where operating voltages are obtained from a 12-cell storage battery, and is designed for operation at a plate-supply voltage having a design-center of 26.5 volts. It is rated in compliance with military standards.

Maximum ratings include a plate voltage of 300 volts (with a separate rating of 330 volts also given), a grid voltage for regular bias of 50 volts, a grid voltage for positive bias of 20 volts, a negative bias voltage of 50 volts, and a positive bias voltage of 0 volts. The maximum cathode current is 20 mA, and the maximum plate dissipation is given as both 2.5 watts and 2.75 watts. The maximum peak heater-cathode voltage is 90 volts with heater negative or positive with respect to cathode, and also 100 volts with heater negative or positive with respect to cathode. The maximum grid circuit resistance is 1.0 megohm.

Applications

The 12SX7GT is useful as an audio amplifier, oscillator, converter, and multi-vibrator. It is a twin triode amplifier with a low B voltage rating.

Capacitances

Grid-to-plate capacitance is 3.6 μμf for triode unit 1 and 3.6 μμf for triode unit 2. Input capacitance is 3.0 μμf for triode unit 1 and 2.8 μμf for triode unit 2. Output capacitance is 0.8 μμf for triode unit 1 and 1.2 μμf for triode unit 2.

Typical Operating Characteristics

At a plate voltage of 26.5 volts, the plate current is 1.8 mA, the plate resistance is 11,500 ohms, the transconductance is 1,800 μmhos, and the amplification factor is 21. At a plate voltage of 90 volts, the plate current is 10 mA, the plate resistance is 6,700 ohms, the transconductance is 3,000 μmhos, and the amplification factor is 20. At a plate voltage of 250 volts, the plate current is 9.0 mA, the plate resistance is 7,700 ohms, the transconductance is 2,600 μmhos, and the amplification factor is 20.

Original manufacturer datasheets for 12SX7GT, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

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