Data set 01
1963 Siemens
Published operating points and test conditions from this source.
SECTION 1
Triode
Other
Heater voltage
6.3 V
Characteristics
Transconductance
7000 µS
Nominal/Bogey
Amplification factor
11.5
Nominal/Bogey
Nuvistor Tubes (all numbers) ·Triode
8056
Industrial medium-mu Nuvistor triode intended for low-voltage industrial amplification and control applications.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- B9A
- Base pins
- 5
- Nominal heater
- 6.3 V / 135 mA
Description
8056 — Low-Voltage Medium-Mu Industrial Nuvistor Triode
Compact metal-shell triode for hybrid electronics, impedance conversion, cathode followers, multivibrators, and low-voltage industrial and military circuits.
Overview
The 8056 is a medium-mu Nuvistor triode specifically designed for low-voltage power supplies. RCA describes industrial and military applications, while Siemens highlights hybrid circuits, impedance-converter stages, cathode followers, and multivibrators. Unlike many receiving tubes characterized at hundreds of volts, the 8056 has published typical operation at only 12 and 24 V plate supply.
The low plate resistance, relatively high transconductance, and amplification factor around 12 are central to the manufacturer's intended applications.
Construction, Heater, and Basing
The 8056 uses a coated, indirectly heated unipotential cathode inside a compact MT4 metal-shell Nuvistor envelope. It has a medium ceramic-wafer E5-65 Twelvar base, 12AQ basing, and requires a Nuvistor socket. RCA permits any mounting orientation.
| Parameter | Value |
|---|---|
| Heater voltage | 6.3 ± 0.6 V |
| Heater current | 135 mA |
| Heater power, calculated | 0.85 W |
| Peak heater-to-cathode voltage | ±100 V |
| Maximum overall length | 0.800 in |
| Maximum seated length | 0.625 in |
| Maximum diameter | 0.440 in |
| Approximate mass | 1.9–2 g |
The RCA underside-view diagram identifies pin 2 as plate, pin 4 as grid, pin 8 as cathode, and pins 10 and 12 as heater. The remaining indexed internal-connection pins must not be used as general-purpose circuit terminals.
Low-Voltage Operating Characteristics
RCA provides two representative low-voltage operating conditions:
| Characteristic | 12 V supply | 24 V supply |
|---|---|---|
| Plate supply voltage | 12 V | 24 V |
| Grid bias | Via 33 kΩ grid resistor | −0.7 V |
| Plate current | 5.5 mA | 9.5 mA |
| Amplification factor | 12 | 12 |
| Plate resistance | Approximately 1.5 kΩ | 1.5 kΩ |
| Transconductance | 8 mA/V | 8 mA/V |
A separate RCA Class A1 characteristic condition uses 24 V supply, 100 Ω cathode resistor, and the grid connected to the negative end of that resistor. It gives 8.7 mA plate current, 7.5 mA/V transconductance, 1,530 Ω plate resistance, and 11.5 amplification factor.
The small-signal relation μ ≈ gₘ × rₚ is consistent with the published figures: 0.0075 S × 1,530 Ω ≈ 11.5.
Cathode-Follower and Impedance-Converter Applications
Siemens explicitly recommends the 8056 for cathode-follower and impedance-transformer stages in hybrid electronics. In a cathode follower, the signal is taken from the cathode circuit and follows the grid's voltage changes, providing a different input-output impedance relationship from a plate-loaded voltage amplifier.
The published low plate resistance and transconductance help explain its suitability for these roles. Siemens also identifies multivibrator circuits, where the tube can be used as a switching and timing element. The datasheets do not specify one universal multivibrator circuit or timing range.
Maximum Ratings
| Parameter | Published maximum |
|---|---|
| Plate voltage | 50 V in detailed RCA HB3 and Siemens data |
| Plate dissipation | 0.45 W |
| Cathode current | 15 mA |
| Negative grid voltage | 55 V |
| Peak positive grid voltage | 2 V |
| Grid current | 2 mA |
| Grid-circuit resistance, fixed bias | 10 MΩ |
| Grid-circuit resistance, cathode bias | 10 MΩ |
The later RCA RC30 condensed table lists 60 V maximum plate voltage, differing from the detailed RCA HB3 and Siemens 50 V figure. This is a documented publication difference; the higher value should not be substituted indiscriminately.
The grid-circuit resistance rating is specified for metal-shell temperatures up to 150°C, with a manufacturer chart for other temperatures.
Interelectrode Capacitances
| Measurement | Typical value |
|---|---|
| Grid to plate | 2.1 pF |
| Grid to cathode, shell, and heater | 4.0 pF |
| Plate to cathode, shell, and heater | 1.7 pF |
| Plate to cathode | 0.34 pF |
| Heater to cathode | 1.4 pF |
These capacitances influence input loading and feedback in hybrid and high-frequency circuit applications.
Industrial Reliability and Qualification
RCA's extensive technical sheet specifies 1,000 g impact-shock testing, 2.5 g fatigue vibration for 48 hours at 60 Hz, variable-frequency vibration tests, low-pressure breakdown testing, heater cycling, and multiple life tests.
The vibration-noise limits include 20 mV RMS at 50–3,000 Hz, 50 mV peak at 3–6 kHz, and 500 mV peak at 6–15 kHz, under the specified test circuit.
The low-pressure breakdown test simulates approximately 100,000 feet altitude with 250 V RMS applied between the plate and the other electrodes.
RCA also specifies a minimum 2,000 heater on/off cycles in its heater-cycling test. Its life qualification includes 20-hour stabilization, 100-hour survival, and 1,000-hour conduction and standby tests. Siemens separately describes a service life exceeding 10,000 hours under its quality specification.
These tests document industrial qualification and should not be confused with unrestricted operating ratings.
Technical Summary
The 8056 is a 6.3 V / 135 mA low-voltage industrial Nuvistor triode with approximately 12 amplification factor, 8 mA/V transconductance, and 1.5 kΩ plate resistance at its published low-voltage operating points.
Its documented applications include hybrid electronic circuits, impedance conversion, cathode followers, multivibrators, and low-voltage industrial and military equipment. Its compact construction, high electrical slope at 12–24 V, and stringent mechanical reliability testing distinguish it from ordinary higher-voltage receiving triodes.
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
- -
- Socket code
- B9A
- Base pins
- 5
- Nominal heater voltage
- 6.3 V
- Nominal heater current
- 135 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
1 physical section, each with unique specifications.
Section 1
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 1530 Ω
- Transconductance
- 0.0075 S
- Amplification factor
- 11.5
- Max plate voltage
- 50 V
- Max plate dissipation
- 0.45 W
- Max cathode current
- 15 mA
Published promoted values applied where semantically applicable; additional source-table values retained in TUBE_SECTION_PARAMETER.
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.
Data set 02
1971 RCA HB3 Binder 3 of 7
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristics
Voltage (AC or DC) — published value 1
6.3 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Voltage (AC or DC) — published value 2
0.6 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Current at heater volts = 6.3 — published value 1
6.3 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Current at heater volts = 6.3 — published value 2
0.135 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid to plate
2.1 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid to .cathode, shell, and heater
4 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode, shell, and heater
1.7 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode — published value 1
0 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode — published value 2
34 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater to cathode
1.4 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Supply Voltage
24 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Resistance (Approx )
1530 ohm
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance
7500
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current
8.7 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid Voltage (Approx.) for plate µa = 50 — published value 1
50 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid Voltage (Approx.) for plate µa = 50 — published value 2
-5 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Pin 2 -Plate
2
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Pin 4 -Grid
4
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Pin 10 -Heater
10
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Pin 12 -Heater
12
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Supply Voltage — published value 1
12 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Supply Voltage — published value 2
24 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid Supply Voltage
0.7 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid Resistor
33000 ohm
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Resistance (Approx ) — published value 1
1500 ohm
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Resistance (Approx ) — published value 2
1500 ohm
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance — published value 1
8000
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance — published value 2
8000
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current — published value 1
5.5 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current — published value 2
9.5 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
peratures above 150° C., see accompanying Cr id-Circuit-Resistance Rating
150
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater Current — published value 1
1
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater Current — published value 2
0.125
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater Current — published value 3
0.145
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid to plate — published value 1
2 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid to plate — published value 2
1.8 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Grid to plate — published value 3
2.4 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 1
2 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 2
3.4 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 3
4.6 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 1
2 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 2
1.4 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
and heater — published value 3
2 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater to cathode — published value 1
2
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater to cathode — published value 2
1.1
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater to cathode — published value 3
1.7
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode — published value 1
2 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode — published value 2
0.26 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate to cathode — published value 3
0.42 pF
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (1) — published value 1
1 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (1) — published value 2
3 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (1) — published value 3
6.7 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (1) — published value 4
10.7 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (21 — published value 1
21
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (21 — published value 2
1
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (21 — published value 3
4
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Plate Current (21 — published value 4
50
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (1) — published value 1
1
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (1) — published value 2
13
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (1) — published value 3
6500
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (1) — published value 4
8500
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (2) — published value 1
2
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (2) — published value 2
35
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Transconductance (2) — published value 3
5700
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Reverse Grid Current — published value 1
16
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Reverse Grid Current — published value 2
0.05
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 1 — published value 1
1 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 1 — published value 2
6.3 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 3 — published value 1
3 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 3 — published value 2
2 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 3 — published value 3
100 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
antl cathode-Dypass Capacitor = 1000 µt
1000
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note LL — published value 1
24 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note LL — published value 2
-10 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 5 — published value 1
5 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 5 — published value 2
5.7 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 6 — published value 1
6 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 6 — published value 2
-2 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 7 — published value 1
7 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 7 — published value 2
100 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 8 — published value 1
8 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 8 — published value 2
100 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Note 9 — published value 1
9 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Other
Heater negative with respect to cathode
100 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Heater positive with respect to cathode
100 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
PLATE VOLTAGE
50 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Negative-bias value
55 V
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
GRID CURRENT
2 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
CATHODE CURRENT
15 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
PLATE DISSIPATION — published value 1
0 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
PLATE DISSIPATION — published value 2
45 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
For fixed-bias operation
10 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
For cathode-bias operation
10 mA
Published datasheet value; multiple numbers on a source row represent separate limits or operating conditions.
Data set 03
1975 RCA RC30
Published operating points and test conditions from this source.
SECTION 1
Triode
Capacitance
Grid to Plate Capacitance
2.1 pF
Heater to Cathode Capacitance
1.4 pF
Other
Typical Plate Supply Voltage
24 V
LowVoltage
Typical Plate Current
9.5 mA
LowVoltage