Data set 01
1960 Mazda
Published operating points and test conditions from this source.
SECTION 1
Tetrode
Characteristics
Filament current minimum
40 mA
Filament current maximum
50 mA
Voltage Tetrode ·Tetrode
6250
Directly heated space-charge-grid electrometer tetrode for extremely high input-resistance measurement circuits. Its specialized grid arrangement supports very-low-current instrumentation.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 2.56 V / 45 mA
Description
Directly heated space-charge-grid electrometer tetrode for extremely high input-resistance measurement circuits.
Socket description
Small-button Noval 9-contact
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater voltage
- 2.56 V
- Nominal heater current
- 45 mA
- 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
Tetrode
X-ray radiationInterelectrode capacitances
- Transconductance
- 0.00004 S
- Amplification factor
- 1.8
- Max plate voltage
- 9 V
Mazda 6250 single directly heated electrometer tetrode, 2.56 V nominal 45 mA filament (40–50 mA published range). Manufacturer maximum anode 9 V, grid No.1 +6 V and grid No.2 negative rating -2 V as printed. Typical operation anode 9 V, space-charge grid No.1 +6 V, measuring grid No.2 -4 V; anode current approximately 75 µA, grid No.1 current approximately 525 µA and amplification factor 1.8. Mazda describes transconductance in an electrode-specific measuring arrangement; previous 0.00004 S field retained pending reconciliation. Measuring grid 2 capacitance to other electrodes 5.8 pF, very high grid insulation (>10^15 Ω) and minute reverse current. One physical tetrode section; measuring grid No.2 connected to top cap.
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
1968 Mazda Belvu
Published operating points and test conditions from this source.
SECTION 1
Tetrode
Other
HeaterVoltageNominal
2.5 V
Nominal
HeaterCurrentNominal
45 mA
Nominal
Maximum Plate Voltage
9 V
Characteristic
Transconductance
40 µS
Typical
Amplification Factor
1.8
Typical