Voltage - Triode (under 100V) ·Triode
Early directly heated triode for general receiving service. Available source material confirms basic triode construction but does not establish a narrower application confidently.
The 00A (also referred to as the 00-A) is a gas-filled, vapor-type three-electrode triode vacuum tube. It is designed specifically for service as a highly sensitive grid-leak detector in storage-battery-operated radio receivers. Primarily utilized for renewal purposes in legacy equipment, the tube features a filamentary cathode and operates at low plate voltages.
The 00A is constructed with an S-14 glass bulb and a medium 4-pin bayonet base. To ensure proper operation and mechanical stability, the tube must be installed in a standard four-contact socket that holds the device in a vertical position.
The physical dimensions of the tube are characterized by the following maximum limits:
The 00A utilizes the standard 4D base connection configuration. When viewed from the bottom of the socket, the pin assignments are as follows:
The 00A features a directly heated filament designed for direct-current (DC) operation, typically supplied by a storage battery.
| Parameter | Value | Unit |
|---|---|---|
| Filament Voltage (D.C.) | 5.0 | V |
| Filament Current | 0.25 | A |
| Maximum Plate Voltage | 45 | V |
Because the 00A is a gas-filled vapor-type tube, its maximum plate voltage is strictly limited to 45 volts to prevent ionization breakdown or damage to the tube structure.
Under typical operating conditions as a detector, the 00A exhibits a high plate resistance and moderate amplification factor. The standard operating parameters are defined as follows:
When configured specifically for grid-leak detector service, the external circuit parameters must be carefully selected to maximize the sensitivity of the gas-filled triode:
The direct interelectrode capacitances of the 00A, measured without an external shield, are as follows:
These capacitance values are critical for determining the input loading and RF performance of the detector stage in storage-battery receivers.
The 00A is a specialized, gas-filled triode detector tube featuring a 5.0 V, 0.25 A DC filament, an S-14 glass envelope, and a medium 4-pin bayonet base. Operating at a maximum plate potential of 45 V, it provides an amplification factor of 20 and a plate resistance of 30,000 ohms under typical zero-bias conditions. Optimized for sensitive grid-leak detection with a 2 to 3 megohm grid leak and a 0.00025 uF condenser, the 00A serves as a critical renewal component for early storage-battery-operated radio receivers, requiring vertical mounting for reliable operation.
Medium-shell UX 4-contact
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 handbook ratings and operating characteristics reviewed.
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.
Plate voltage
45 V
Grid bias
0 V
Plate current
1.5 mA
Approximate
Plate voltage
45 V
Detector; GridLeak
Grid leak resistance
2 to 3 MOhm
Detector; GridLeak
Grid condenser
0.0025 uF
Detector; GridLeak
Grid-to-plate capacitance
8.5 pF
Input capacitance
3.2 pF
Output capacitance
2 pF
Data set 02
Published operating points and test conditions from this source.
Application
Detector text
Data set 03
Published operating points and test conditions from this source.
Maximum plate voltage
45 V
Published handbook rating
Plate voltage
45 V
ClassA
Control-grid bias
0 V
ClassA
Plate current
1.5 mA
ClassA
Plate resistance
30000 ohm
Published handbook characteristic
Transconductance
666 µS
Published handbook characteristic
Amplification factor
20
Published handbook characteristic
Heater/filament voltage
5 V
Published heater/filament rating
Heater/filament current
250 mA
Published heater/filament rating