Voltage Regulator ·VoltageRegulator
Gas-filled 75 V voltage regulator operating over approximately 5–40 mA for heaterless shunt stabilization and reference circuits.
OA3 is a printed exact equivalent/co-designation on the STR7540 source sheet. A 75 V cold-cathode glow-discharge regulator with a radioactive starting aid; the source states that no harmful radiation is produced.
International Octal
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
| Terminal | Section | Connection | Evidence |
|---|---|---|---|
| PIN2K | A | K — Cathode | Unverified EIA Base Connections, printed page 127, 4AJ |
| PIN5P | A | P — Plate (Anode) | Unverified EIA Base Connections, printed page 127, 4AJ |
1 physical section, each with unique specifications.
Section 1
Published maximum ratings and characteristics audited; remaining useful numerical data retained in parameter table.
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.
Maximum stabilising voltage at 40 mA
81 V
Published datasheet value
Maximum peak current
100 mA
Published datasheet value
Minimum stabilising voltage at 5 mA
70 V
Published datasheet value
Data set 02
Published operating points and test conditions from this source.
Nominal maintaining voltage
75 V
Voltage variation over current range
4 V
Current range
5 to 40 mA
Nominal current
20 mA
Radioactive starting aid
present
No harmful radiation stated by source
Data set 03
Published operating points and test conditions from this source.
VOLTAGE STABILISER QS1 [1]
50 V
VOLTAGE STABILISER QS150/40
VOLTAGE STABILISER QS1 [2]
40 V
VOLTAGE STABILISER QS150/40
Stability {( [1]
1000
Stability {(1000 hr, period) *2 ¥2 %
Stability {( [2]
2
Stability {(1000 hr, period) *2 ¥2 %
Stability {( [3]
2
Stability {(1000 hr, period) *2 ¥2 %
Published value
10 mA
10 mA should be allowed in addition to the load current.
Stabilized voltage
75 V
Published regulated voltage.
Tube current minimum
5 mA
Minimum maintaining current.
Tube current maximum
40 mA
Maximum operating current.
Ignition voltage
105 V
Published minimum or maximum ignition/start voltage as applicable.
Data set 04
Published operating points and test conditions from this source.
Average starting current
100 mA
DC cathode current
5 mA to 40 mA
Ambient temperature range
-55 to +90 C
Maximum shunt capacitance
0.1 uF
Minimum DC anode supply voltage
105 V
Anode breakdown / starting voltage
105 V
Anode voltage drop
68 to 85 V
Regulation over specified cathode-current range
- to 6.5 V