Voltage Regulator ·VoltageRegulator
Low-current cold-cathode regulator operating around 59 V, also usable as a relaxation-oscillator timing element.
The 991 is a cold-cathode glow-discharge voltage-regulator tube with a candelabra double-contact base. It is intended for regulated DC power supplies and may also be used in relaxation-oscillator circuits. The source table gives a 0.4–2.0 mA operating-current range, about 59 V operating voltage, and about 87 V starting voltage.
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
Published ratings and characteristics promoted from approved datasheet.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Operating current range
0.4 to 2 mA
Starting voltage
87 V
Operating voltage
59 V
Voltage regulation
8 V
Application
DC voltage regulation / relaxation oscillator
Base
Candelabra double-contact
Data set 02
Published operating points and test conditions from this source.
Minimum starting-supply voltage
87 to - V
Operating voltage range
48 to 67 V
Maximum peak current
3 mA
Maximum continuous DC current
2 mA
Operating current range
0.4 to 2 mA