2B5

Sylvania 2B5 directly heated subminiature dual HF triode for voltage amplification to 150 MHz, with selectable 2 V series or 1.2 V parallel filament configuration.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: -
Base pins: 8
Nominal heater: 2 V / 130 mA

Description

Subminiature double triode capable of operation to 150 MHz as a voltage amplifier.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: 8
Nominal heater voltage: 2 V
Nominal heater current: 130 mA
Parallel heater voltage: 1.2 V
Parallel heater current: 260 mA
Series capable: Yes

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 18700 Ω
Transconductance: 0.00115 S
Amplification factor: 21.5
Max plate voltage: 110 V
Max plate dissipation: 0.55 W
Max cathode current: 5 mA

Sylvania RTMA 1951 2B5 physical triode section 1. Design-center maximum plate 110 V, dissipation 0.55 W, cathode current 5 mA, grid voltage positive max 0 V and negative limit -20 V. Typical at plate 90 V, grid -1 V, filament 1.2 V parallel: Ia 2.6 mA, gm 0.00115 A/V, mu 21.5, rp 18700 Ω. Grid-plate capacitance 1.2 pF; shielded/unshielded input 0.9/0.8 pF, output 1.9/0.8 pF. Cross-section grid-grid unshielded 0.046 pF, plate-plate 0.7 pF. Series filament requires external balancing resistor; 8DP flexible lead basing.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 18700 Ω
Transconductance: 0.00115 S
Amplification factor: 21.5
Max plate voltage: 110 V
Max plate dissipation: 0.55 W
Max cathode current: 5 mA

Sylvania RTMA 1951 2B5 physical triode section 2. Design-center maximum plate 110 V, dissipation 0.55 W, cathode current 5 mA, grid voltage positive max 0 V and negative limit -20 V. Typical at plate 90 V, grid -1 V, filament 1.2 V parallel: Ia 2.6 mA, gm 0.00115 A/V, mu 21.5, rp 18700 Ω. Grid-plate capacitance 1.2 pF; shielded/unshielded input 0.9/0.7 pF, output 2.2/0.9 pF. Cross-section grid-grid unshielded 0.046 pF, plate-plate 0.7 pF. Series filament requires external balancing resistor; 8DP flexible lead basing.

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 01

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

operation up to 150 megacycles as a voltage amplifier,
150 MHz
operation up to 150 megacycles as a voltage amplifier,
Fllament Voltage .eveeeecevosssnnsnee Lot 1,2 volts
1.2 V
Fllament Voltage .eveeeecevosssnnsnee Lot 1,2 volts
Plate Voltage (dc).....-o.-oooouoo--auon----- 90 volts
90 V
Plate Voltage (dc).....-o.-oooouoo--auon----- 90 volts
OGrid Voltage (AC).eerececsssossresosnnncannes -1.0 volts
-1 V
OGrid Voltage (AC).eerececsssossresosnnncannes -1.0 volts
Grid Voltage for 10 uamps Flate Current .ecccees 6.0 volts
6 V
Grid Voltage for 10 uamps Flate Current .ecccees 6.0 volts

Other

Maximum Plate Dissipation {each section)eceseees 0.55 watts
0.55 W
Maximum Plate Dissipation {each section)eceseees 0.55 watts