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12AZ7 tube: datasheets and technical data
Explore available pinout, electrical data and related types for the 12AZ7 vacuum tube.
The 12AZ7 is a miniature nine-pin twin triode, with the cathodes of the two sections brought out to separate contacts. RCA describes it as a high-mu tube for several stages of VHF television receivers, including cathode-drive amplification and frequency conversion. Tung-Sol also mentions use as an audio-frequency amplifier or as a combined oscillator and mixer. These are applications proposed in the respective sheets, not circuit configurations that are automatically interchangeable.
The center-tapped heater permits two connections: 12.6 V at 0.225 A between pins 4 and 5, or 6.3 V at 0.45 A with pins 4 and 5 tied together and supplied relative to pin 9. Viewed from below, the first triode has its plate on pin 6, grid on 7 and cathode on 8; the second has its plate on 1, grid on 2 and cathode on 3. The separate cathodes allow flexibility in bias circuits, but heater wiring must be checked before replacing a tube in an existing set.
For each triode, RCA gives design-center maxima of 300 V plate voltage and 2.5 W plate dissipation. A Class A1 operating point with a 100 V plate supply and a 270 Ω cathode resistor gives about 3.7 mA plate current and 4 mA/V transconductance. At 250 V with 200 Ω in the cathode circuit, the sheet lists 10 mA and 5.5 mA/V. In both cases the tabulated amplification factor is 60. These are operating examples for the individual sections, separate from the maximum ratings and dependent on the chosen bias.
Tube images
Pinout and connections
Base: Noval (B9A)
Electrical data
Heater
- Heater voltage Vh
- 12.6 V
- Heater current Ih
- 0.225 A
Maximum ratings
- Maximum anode dissipation Pa max
- 2.5 W
Datasheet PDF
EL84 ECC83 12AX7 EL34 6L6GC 300B KT88 GZ34
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