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75TH

Eimac medium-mu transmitting triode for RF amplification, oscillation, and audio modulation. Rated around 75 W plate dissipation, it provides substantial Class C RF output or higher combined output from a two-tube modulator.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: MEDIUM4BAYONET
Base pins: -
Nominal heater: 5 V / 6.25 A

Description

Medium-mu transmitting triode for RF amplifier, oscillator, and audio modulator service.

Socket description

Medium 4-contact bayonet base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: MEDIUM4BAYONET
Base pins: -
Nominal heater voltage: 5 V
Nominal heater current: 6.25 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: 0.00415 S
Amplification factor: 20
Max plate voltage: 3000 V
Max plate dissipation: 75 W
Max grid dissipation: 16 W
Max cathode current: 225 mA

Promoted maximum ratings/characteristics populated from published headings; service-specific values retained in parameters.

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 Eimac Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Filament Voltage
5 V
Filament Current
6.25 A
Amplification Factor
20
Transconductance
4150 uS

Capacitance

Grid-Plate Capacitance
2.3 pF
Grid-Filament Capacitance
2.7 pF
Plate-Filament Capacitance
0.3 pF

Other

Maximum DC Plate Voltage
3000 V
RF Class C and audio service
Maximum DC Plate Current
225 mA
RF Class C
Maximum Plate Dissipation
75 W
Maximum Grid Dissipation
16 W
Frequency Limit for Published RF Ratings
40 MHz
Typical RF Plate Output
225 W
Class C; 2 kV plate
Typical Audio Plate Output
300 W
Two tubes, Class B; 2 kV plate

Construction

Cooling
Radiation and air circulation

Data set 02

1962 Eimac

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

} The Eimac
75
} The Eimac 75TH is a medium-mu power triode intended for use as an amplifier, oscillator, or
modulator. I+ has a maximum plate dissipation rating of
75 W
modulator. I+ has a maximum plate dissipation rating of 75 watts and a maximum plate voltage rating
The [1]
75 W
The 75TH in Class-C R-F service will deliver up to 225 watts plate power output with 10 watts
The [2]
225 W
The 75TH in Class-C R-F service will deliver up to 225 watts plate power output with 10 watts
The [3]
10 W
The 75TH in Class-C R-F service will deliver up to 225 watts plate power output with 10 watts
driving power. Two [1]
75 W
driving power. Two 75TH's in Class-B modulator service will deliver up to 300 watts maximum-signal
driving power. Two [2]
300 W
driving power. Two 75TH's in Class-B modulator service will deliver up to 300 watts maximum-signal
plate power output with
3 W
plate power output with 3 watts driving power.
Voltage
5 V
Voltage - - - - - - - - - - - - - 5.0 volts
Current
6.25 A
Current - . - - - - - - - - - - - 6.25 amperes
Amplification Factor (Average}
20
Amplification Factor (Average} - - - - - - - - - - - - 20
Transconductance (l,= [1]
225 mA
Transconductance (l,=225 ma., E;=3000 v.} - - - - - - - 4150 ymhos
Transconductance (l,= [2]
3000 mA
Transconductance (l,=225 ma., E;=3000 v.} - - - - - - - 4150 ymhos
Transconductance (l,= [3]
4150 mA
Transconductance (l,=225 ma., E;=3000 v.} - - - - - - - 4150 ymhos
‘ Highest Frequency for Maximum Ratings
40 MHz
‘ Highest Frequency for Maximum Ratings - - - - - - - - - 40 Mc
RADIO FRE°UENCY POWER AMPLIFIER TYPICAL OPERATION (Frequencies up to
40 MHz
RADIO FRE°UENCY POWER AMPLIFIER TYPICAL OPERATION (Frequencies up to 40 Mc.)
D-C Plate Voltage [1]
1000 V
D-C Plate Voltage - - - - - 1000 1500 2000 volts
D-C Plate Voltage [2]
1500 V
D-C Plate Voltage - - - - - 1000 1500 2000 volts
D-C Plate Voltage [3]
2000 V
D-C Plate Voltage - - - - - 1000 1500 2000 volts
MAXIMUM RATINGS (Frequencies up to [1]
40 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) p Peak R-F Grid Inpyt Voltage (approx.) 270 280 350 \rrnoalfs
MAXIMUM RATINGS (Frequencies up to [2]
270 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) p Peak R-F Grid Inpyt Voltage (approx.) 270 280 350 \rrnoalfs
MAXIMUM RATINGS (Frequencies up to [3]
280 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) p Peak R-F Grid Inpyt Voltage (approx.) 270 280 350 \rrnoalfs
MAXIMUM RATINGS (Frequencies up to [4]
350 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) p Peak R-F Grid Inpyt Voltage (approx.) 270 280 350 \rrnoalfs
D-C PLATE VOLTAGE [1]
3000 V
D-C PLATE VOLTAGE - - - - - 3000 MAX. VOLTS Driving Power {approx.} - - 9 [ 10 watts
D-C PLATE VOLTAGE [2]
9 V
D-C PLATE VOLTAGE - - - - - 3000 MAX. VOLTS Driving Power {approx.} - - 9 [ 10 watts
D-C PLATE VOLTAGE [3]
10 V
D-C PLATE VOLTAGE - - - - - 3000 MAX. VOLTS Driving Power {approx.} - - 9 [ 10 watts
D-C PLATE CURRENT [1]
225 mA
D-C PLATE CURRENT - - - - - 225 MAX. MA Plate Power Input - - - - - 215 250 300 watts
D-C PLATE CURRENT [2]
215 mA
D-C PLATE CURRENT - - - - - 225 MAX. MA Plate Power Input - - - - - 215 250 300 watts
D-C PLATE CURRENT [3]
250 mA
D-C PLATE CURRENT - - - - - 225 MAX. MA Plate Power Input - - - - - 215 250 300 watts
D-C PLATE CURRENT [4]
300 mA
D-C PLATE CURRENT - - - - - 225 MAX. MA Plate Power Input - - - - - 215 250 300 watts
PLATE DISSIPATION [1]
75 W
PLATE DISSIPATION - - - - - 75 MAX. WATTS Plate Dissipation - - - - - 75 75 75 watts
PLATE DISSIPATION [2]
75 W
PLATE DISSIPATION - - - - - 75 MAX. WATTS Plate Dissipation - - - - - 75 75 75 watts
PLATE DISSIPATION [3]
75 W
PLATE DISSIPATION - - - - - 75 MAX. WATTS Plate Dissipation - - - - - 75 75 75 watts
PLATE DISSIPATION [4]
75 W
PLATE DISSIPATION - - - - - 75 MAX. WATTS Plate Dissipation - - - - - 75 75 75 watts
GRID DISSIPATION [1]
16 W
GRID DISSIPATION - - - - - 16 MAX. WATTS Plate Power Output - - - - 140 175 225 watts
GRID DISSIPATION [2]
140 W
GRID DISSIPATION - - - - - 16 MAX. WATTS Plate Power Output - - - - 140 175 225 watts
GRID DISSIPATION [3]
175 W
GRID DISSIPATION - - - - - 16 MAX. WATTS Plate Power Output - - - - 140 175 225 watts
GRID DISSIPATION [4]
225 W
GRID DISSIPATION - - - - - 16 MAX. WATTS Plate Power Output - - - - 140 175 225 watts
D-C Plate Voltage [1]
1000
D-C Plate Voltage - - - - - 1000 1500 2000 I
D-C Plate Voltage [2]
1500
D-C Plate Voltage - - - - - 1000 1500 2000 I
D-C Plate Voltage [3]
2000
D-C Plate Voltage - - - - - 1000 1500 2000 I
FREQUENCY AMPLIFIER D-C Grid Voltage - - - - IS0 [1]
-200
FREQUENCY AMPLIFIER D-C Grid Voltage - - - - IS0 —200 —300 valts
FREQUENCY AMPLIFIER D-C Grid Voltage - - - - IS0 [2]
-300
FREQUENCY AMPLIFIER D-C Grid Voltage - - - - IS0 —200 —300 valts
MAXIMUM RATINGS (Frequencies up to [1]
40 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) Peak R-F Grid Input Voltage (approx.) 300 330 440 ‘r/noalfs
MAXIMUM RATINGS (Frequencies up to [2]
300 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) Peak R-F Grid Input Voltage (approx.) 300 330 440 ‘r/noalfs
MAXIMUM RATINGS (Frequencies up to [3]
330 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) Peak R-F Grid Input Voltage (approx.) 300 330 440 ‘r/noalfs
MAXIMUM RATINGS (Frequencies up to [4]
440 MHz
MAXIMUM RATINGS (Frequencies up to 40 Mc.) Peak R-F Grid Input Voltage (approx.) 300 330 440 ‘r/noalfs
D-C PLATE YOLTAGE
2400
D-C PLATE YOLTAGE - - - - - 2400 MAX. YOLTS Driving Power (approx.)
PLATE DISSIPATION [1]
50 W
PLATE DISSIPATION - - - - - 50 MAX. WATTS Plate Dissipation - - - - 50 50 50 watds
PLATE DISSIPATION [2]
50 W
PLATE DISSIPATION - - - - - 50 MAX. WATTS Plate Dissipation - - - - 50 50 50 watds
PLATE DISSIPATION [3]
50 W
PLATE DISSIPATION - - - - - 50 MAX. WATTS Plate Dissipation - - - - 50 50 50 watds
PLATE DISSIPATION [4]
50 W
PLATE DISSIPATION - - - - - 50 MAX. WATTS Plate Dissipation - - - - 50 50 50 watds
GRID DISSIPATION [1]
16 W
GRID DISSIPATION - - - - - - 16 MAX. WATTS Plate Power Output - - - - - 85 125 170 watts
GRID DISSIPATION [2]
85 W
GRID DISSIPATION - - - - - - 16 MAX. WATTS Plate Power Output - - - - - 85 125 170 watts
GRID DISSIPATION [3]
125 W
GRID DISSIPATION - - - - - - 16 MAX. WATTS Plate Power Output - - - - - 85 125 170 watts
GRID DISSIPATION [4]
170 W
GRID DISSIPATION - - - - - - 16 MAX. WATTS Plate Power Output - - - - - 85 125 170 watts
D-C Plate Voltage [1]
1000
D-C Plate Voltage - - - - - 1000 1500 2000 1t
D-C Plate Voltage [2]
1500
D-C Plate Voltage - - - - - 1000 1500 2000 1t
D-C Plate Voltage [3]
2000
D-C Plate Voltage - - - - - 1000 1500 2000 1t
D-C Plate Voltage [4]
1
D-C Plate Voltage - - - - - 1000 1500 2000 1t
Class-B Zero-Signal D-C Plate Current [1]
90 mA
Class-B Zero-Signal D-C Plate Current - - 90 &7 50 ma.
Class-B Zero-Signal D-C Plate Current [2]
7 mA
Class-B Zero-Signal D-C Plate Current - - 90 &7 50 ma.
Class-B Zero-Signal D-C Plate Current [3]
50 mA
Class-B Zero-Signal D-C Plate Current - - 90 &7 50 ma.
D-C PLATE VOLTAGE - < [1]
3000 V
D-C PLATE VOLTAGE - < - 3000 MAX. YVOLTS Peak A-F Grid Input Yoltage (per tube} 175 165 175 volts
D-C PLATE VOLTAGE - < [2]
175 V
D-C PLATE VOLTAGE - < - 3000 MAX. YVOLTS Peak A-F Grid Input Yoltage (per tube} 175 165 175 volts
D-C PLATE VOLTAGE - < [3]
165 V
D-C PLATE VOLTAGE - < - 3000 MAX. YVOLTS Peak A-F Grid Input Yoltage (per tube} 175 165 175 volts
D-C PLATE VOLTAGE - < [4]
175 V
D-C PLATE VOLTAGE - < - 3000 MAX. YVOLTS Peak A-F Grid Input Yoltage (per tube} 175 165 175 volts
Max-Signal Driving Power {approx.) [1]
7
Max-Signal Driving Power {approx.) - 7 4 3 walts
Max-Signal Driving Power {approx.) [2]
4
Max-Signal Driving Power {approx.) - 7 4 3 walts
Max-Signal Driving Power {approx.) [3]
3
Max-Signal Driving Power {approx.) - 7 4 3 walts
MAX-SIGNAL D-C PLATE CURRENT [1]
225 mA
MAX-SIGNAL D-C PLATE CURRENT - - 225 MAX. MA. max glgna: P;iafe Dlpssapahg\ (per tube) 75 75 75 watts
MAX-SIGNAL D-C PLATE CURRENT [2]
75 mA
MAX-SIGNAL D-C PLATE CURRENT - - 225 MAX. MA. max glgna: P;iafe Dlpssapahg\ (per tube) 75 75 75 watts
MAX-SIGNAL D-C PLATE CURRENT [3]
75 mA
MAX-SIGNAL D-C PLATE CURRENT - - 225 MAX. MA. max glgna: P;iafe Dlpssapahg\ (per tube) 75 75 75 watts
MAX-SIGNAL D-C PLATE CURRENT [4]
75 mA
MAX-SIGNAL D-C PLATE CURRENT - - 225 MAX. MA. max glgna: P;iafe Dlpssapahg\ (per tube) 75 75 75 watts
ax-Signa ate Power Output [1]
200
ax-Signa ate Power Output - - 200 250 300 t
ax-Signa ate Power Output [2]
250
ax-Signa ate Power Output - - 200 250 300 t
ax-Signa ate Power Output [3]
300
ax-Signa ate Power Output - - 200 250 300 t
PLATE DISSIPATION L [1]
75 W
PLATE DISSIPATION L 75 MAX. WATTS P Total Harmonic Distortion - - - 1.5 2.0 2.0 ‘;:r ::enf
PLATE DISSIPATION L [2]
1.5 W
PLATE DISSIPATION L 75 MAX. WATTS P Total Harmonic Distortion - - - 1.5 2.0 2.0 ‘;:r ::enf
PLATE DISSIPATION L [3]
2 W
PLATE DISSIPATION L 75 MAX. WATTS P Total Harmonic Distortion - - - 1.5 2.0 2.0 ‘;:r ::enf

Data set 03

1965 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Amplification Factor
20
Grid Dissipation Maximum
16 W
Frequency Maximum
40 MHz
Typical Class-C Output Power
225 W
Typical Two-Tube Modulator Output Power
350 W