Voltage Triode Pentode ·Pentode-Triode
12JN8
Pentode-triode combination tube; available source material does not establish a narrower functional application confidently.
- Sections
- 2
- Base
- 9FA
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 12.6 V / 225 mA
Description
— e 12JN8 12JN8 Triode-Pentode. The 12JN8 is a miniature tube containing a medium-mu triode and a sharp-cutoff pentode. Except for
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
- 9FA
- Socket code
- B9A
- Base pins
- 9
- Nominal heater voltage
- 12.6 V
- Nominal heater current
- 225 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
9FA - Terminal pinout
Electrical assignments shared by every tube using this base designation.
| Terminal | Section | Connection | Evidence |
|---|---|---|---|
| PIN1Base Pin | B | G1 — Control Grid Original chart label: 2G1; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN2Base Pin | B | P — Plate (Anode) Original chart label: 2P; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN3Base Pin | B | K — Cathode Original chart label: 2K; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN4Base Pin | — | H — Heater Original chart label: H; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN5Base Pin | — | H — Heater Original chart label: H; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN6Base Pin | A | P — Plate (Anode) Original chart label: 1P; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN7Base Pin | A | G2 — Screen Grid Original chart label: 1G2; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN8Base Pin | A | G3 — Suppressor GridGroup 9FA8 Original chart label: 1G3; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN8Base Pin | A | K — CathodeGroup 9FA8 Original chart label: 1K; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
| PIN8Base Pin | — | IS — Internal ScreenGroup 9FA8 Original chart label: IS; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9FA |
Section ratings
2 physical sections, each with unique specifications.
Section 1
Triode
- Plate resistance
- 5400 Ω
- Transconductance
- 0.0085 S
- Amplification factor
- 46
- Max plate voltage
- 300 V
- Max plate dissipation
- 2.5 W
Sylvania 12JN8 medium-mu triode for television horizontal-deflection oscillator and general amplification. At Va 125 V, grid -1 V: gm 8.5 mA/V, amplification factor 46 and plate resistance approximately 5400 ohms; anode current 13.5 mA. Maximum plate voltage 300 V and dissipation 2.5 W. Separate sharp-cutoff pentode section in same 12.6 V, 225 mA tube.
Section 2
Pentode
- Plate resistance
- 200000 Ω
- Transconductance
- 0.0075 S
- Max plate voltage
- 300 V
- Max screen voltage
- 300 V
- Max plate dissipation
- 2.5 W
- Max screen dissipation
- 0.55 W
Sylvania 12JN8 sharp-cutoff TV pentode used with triode oscillator in 12.6 V, 225 mA heater tube. Maximum plate 300 V, screen supply 300 V and plate dissipation 2.5 W, screen dissipation 0.55 W; actual operating screen voltage has rating-chart constraints. Typical at anode 125 V, screen 125 V, control grid -1 V: gm 7.5 mA/V and approximate plate resistance 200 kΩ, anode current 12 mA. Keep screen-supply maximum distinct from 125 V typical grid-2 voltage.
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.