8940

Rugged ceramic-metal planar triode for CW and pulsed RF amplification, frequency multiplication, modulation, and series-regulator service. Its very high transconductance and 6.5 kV capability provide high gain across unusually diverse power applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 6.3 V / 2.25 A

Description

The EIMAC 8940 is a rugged ceramic/metal planar triode for cw and pulsed rf, multiplier, modulator, and series-regulator service.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 2.25 A
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

Transconductance: 0.1 S
Amplification factor: 65
Max plate voltage: 6500 V
Max plate dissipation: 750 W
Max grid dissipation: 2 W
Max cathode current: 16 A

Promoted from printed general-characteristics and absolute-maximum-ratings blocks.

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

1962 Eimac

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Amplification factor
65
Transconductance
100000 uS

Other

Maximum DC plate voltage
4000 V
Maximum plate dissipation
750 W
Maximum grid dissipation
2 W
Maximum pulse cathode current
16 A

Data set 02

1975 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater voltage nominal
6.3 V
Heater current nominal
2.25 A
Transconductance
100000 uS
Amplification factor
65

Capacitance

Input/grid-cathode capacitance
16 pF
Output/plate-cathode capacitance
0.11 pF
Grid-plate/feedback capacitance
3.8 pF

Other

Maximum plate voltage
6500 V
Maximum plate dissipation
750 W
Maximum grid dissipation
2 W
Maximum cathode or pulse plate current
16 A
Maximum rated frequency
2.5 GHz
Grid-pulsed DC plate voltage
4000 V
GridPulsed
Plate-pulsed peak plate voltage
6500 V
PlatePulsed
Pulse plate current
12 A
Pulse grid current
4 A
Pulse duration
6 us
Duty factor
0.0033
Representative peak video plate current
6 A
PlatePulsedOscillator
Representative useful output
10000 W
PlatePulsedOscillator
CW maximum rated frequency
2 GHz
CW

Data set 03

1976 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater voltage nominal
6.3 V
Heater current nominal
2.25 A
Transconductance
100000 uS
Amplification factor
65

Capacitance

Input/grid-cathode capacitance
16 pF
Output/plate-cathode capacitance
0.11 pF
Grid-plate/feedback capacitance
3.8 pF

Other

Maximum plate voltage
6500 V
Maximum plate dissipation
750 W
Maximum grid dissipation
2 W
Maximum cathode or pulse plate current
16 A
Maximum rated frequency
2.5 GHz
Grid-pulsed DC plate voltage
4000 V
GridPulsed
Plate-pulsed peak plate voltage
6500 V
PlatePulsed
Pulse plate current
12 A
Pulse grid current
4 A
Pulse duration
6 us
Duty factor
0.0033
Representative peak video plate current
6 A
PlatePulsedOscillator
Representative useful output
10000 W
PlatePulsedOscillator
CW maximum rated frequency
2 GHz
CW