7740

Sealed steel-envelope ignitron for low-inductance capacitor-discharge circuits, designed to switch extremely high pulse currents at voltages up to about 20 kV.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: -

Description

Westinghousé 7740 June 1, 1960 IGNITRON FOR CAPACITOR DISCHARGE SERVICE TYPE 7740 The 7740 is a sealed, steel envelope tube with Shoop sprayed area where contact is made to the cathode. The anode connection is o threaded stud. The combination is suitable for connection in low inductance, high current cirevits as used in high current capaciter discharge circuits operating up to 20000 volts. In this service the tube will discharge up to 35000 amperes. GENERAL MAXIMUM RATINGS FOR CAPACITOR DISCHARGE Mumber of Electrades Paaok Anode Voltage (Note 2) Inverse . . . u v i e e e 20080 max, Volts Anodes . . i i e e e e e e e e 1 F d (Note 3) 20000 Vol Cathodas . . o v i it s e e s e e 1 orwar Ore Sl max. els [T =Y 1 Ancde Current lanitor Firing Circoit Peok .. ... .. ... . ... ... 35000 max, Ampere trin ir 1 g r 9 o Coulombs Per Discharge . .. .. .. .. 18.6 max. Amp. Sec. Capacitor, v v v v i e e e e 0.5 i Repitition Rate . . . ... .. ....... 2 max, Per Minute Capacitor Yoltage . . .. .........

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: -
Nominal heater current: -
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

IgnitronPowerSwitch

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Source-derived physical/electrical section.

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

1947 Westinghouse

Published operating points and test conditions from this source.

SECTION 1

IgnitronPowerSwitch

Characteristic

cirevits as used in high current capaciter discharge circuits operating up to
20000
cirevits as used in high current capaciter discharge circuits operating up to 20000 volts. In this service the tube

Other

will discharge up to
35000
will discharge up to 35000 amperes.
Mumber of Electrades Paaok Anode Voltage (Note
2
Mumber of Electrades Paaok Anode Voltage (Note 2)
Inverse . . . u v i e e e
20080
Inverse . . . u v i e e e 20080 max, Volts
lanitor Firing Circoit Peok
35000
lanitor Firing Circoit Peok .. ... .. ... . ... ... 35000 max, Ampere
g r
18.6
g r 9 o Coulombs Per Discharge . .. .. .. .. 18.6 max. Amp. Sec.
Capacitor Yoltage
5000
Capacitor Yoltage . . .. ................ 2.5 Kilovolts Rise Time . ... ... ... v, 5000 max, Amps/usec
Series Resistor . . v . v v v v i i v v it e
0.6
Series Resistor . . v . v v v v i i v v it e 10 Ohms Average Current. . . . . v v v e v i e 0.6 max, Ampera
Mopimum Tube .‘: ’ Ap‘erlo;
6
Mopimum Tube .‘: ’ Ap‘erlo; ................... 6.0 °C': ancde. During operation the anode must always be at
& _—
140
& _—1 {iétz,_z inta metal block heated ta 140°C for six to eight hours.
3 -20 THREAD NC ;;5’; —] 2/;’ * 3" method to 25°C or less.
25
3 -20 THREAD NC ;;5’; —] 2/;’ * 3" method to 25°C or less.
fy/ﬁ/
3
fy/ﬁ/ 1;;; MIN, Mote 3: Forward voltage (Hold-off voltage) is the voltage to which
duction of anode voltage to
90
duction of anode voltage to 90% of the forward voltage.
0 10° 20° 3¢° 40° 50°
50
0 10° 20° 3¢° 40° 50°
Anode Fall Time is the time for anode voltage to fall from
10
Anode Fall Time is the time for anode voltage to fall from 90% to 10% of the for-
Jitter is the variotion in time for anode voltage to fall to
50
Jitter is the variotion in time for anode voltage to fall to 50% of the forward