Data set 01
1956 Western Electric Tubes
Published operating points and test conditions from this source.
SECTION 1
Rectifier
Characteristic
HeaterOrFilamentVoltage
2.5 V
HeaterOrFilamentCurrent
7 A
Rectifier - Half Wave ·Rectifier
287A
Directly heated mercury-vapor rectifier for special-purpose power supplies. Rated for approximately 2.5 kV peak inverse voltage, 640 mA DC output, and 2.5 A peak current.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- MEDIUM5
- Base pins
- 5
- Nominal heater
- 2.5 V / 7 A
Description
Mercury-vapor special-purpose diode/rectifier.
Socket description
Medium 5-contact transmitting-tube base
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- MEDIUM5
- Base pins
- 5
- Nominal heater voltage
- 2.5 V
- Nominal heater current
- 7 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
Rectifier
X-ray radiationInterelectrode capacitances
- Rectifier peak inverse voltage
- 2500 V
- Rectifier nominal output current
- 640 mA
- Rectifier peak forward current
- 1 A
- Rectifier forward voltage drop
- 15 V
- Rectifier warm-up time
- 10 s
Thyratron; published conduction ratings mapped to applicable rectifier-like fields.
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 02
2026 Western Electric 200s
Published operating points and test conditions from this source.
SECTION 1
Rectifier
Characteristic
Maximum Time Averaging Anode Current
5 s
Maximum Instantaneous Grid Current
50 mA
Operating Temperature Minimum
30 C
Operating Temperature Maximum
80 C
Nominal Deionization Time
1000 us
Data set 03
2026 Western Electric 300s
Published operating points and test conditions from this source.
SECTION 1
Rectifier
Other
Maximum peak voltage between anode and grid
2500 V
Maximum instantaneous anode current
1 A
Characteristic
Approximate tube voltage drop
15 V
Conducting