| GENERAL DESCRIPTION |
|
The 813 / QB2/250 is a five-electrode beam-power transmitting tube of high sensitivity, designed for use as a modulator, amplifier, and oscillator. The anode is capable of dissipating 125 watts. The cathode is a thoriated-tungsten filament. Maximum ratings apply up to a frequency of 30 megacycles. Cooling is obtained by radiation. For continuous commercial service the output for Class C telegraph service is 275 watts. With adequately shielded circuits neutralization is unnecessary. |
| TECHNICAL SPECIFICATIONS | ||||
| ELECTRICAL | ||||
| Min. | Bogey | Max. | ||
| Filament Voltage | 9.5 | 10 | 10.5 | volts |
| Filament Current at Bogey Voltage | 4.7 | 5 | 5.3 | amp |
| Transconductance | 3750 µmhos | |||
| Amplification factor | 8.5 | |||
| Interelectrode Capacitances, measured without external shielding G1 to Plate Input, G1 to Filament, G2 and G3 Output, plate to filament, G2 and G3 |
13 10.5 |
16.3 14 |
0.25 19.6 17.5 |
µµf µµf µµf |
| MECHANICAL | ||||
| Mounting Position | Vertical, base up or down Horizontal, plate in vertical plane |
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| Basing | JETEC 5BA | |||
| Cap, medium | JETEC C1-5 | |||
| Base, medium metal-shell, giamt 7-pin bayonet | JETEC A7-17 | |||
| Bulb | T-20 | |||
| Net Weight, approximate | 8 oz. | |||
| Shipping Weight | 2.5 lbx | |||
| Specifications may change without notice | ||||
| THIS TUBE IS USED IN THE FOLLOWING SHORTWAVE BROADCAST TRANSMITTERS | ||
| Manufacturer | Transmitter specifications | Power in kW |
| Gates | HF-50 C | 50 |
| HF-100 C | 100 | |
| Marconi | BD 272 | 250 |
| RCA | BHF-10A | 10 |
| BHF-50A | 50 | |
| BHF-50B | 50 | |
| THIS TUBE IS AVAILABLE FROM | ||
| Manufacturer | Rebuilder | Distributor |
| Penta Laboratories | Richardson Electronics | |
| Vacuum Tubes, Inc. | ||
| PRICE LEVEL (US$) | |||||
| 1 | 2 | 3 | 4 | 5 | 6 |
| 0 - 10 | 10 - 100 | 100 - 1000 | 1000 - 10,000 | 10,000 - 50,000 | 50,000 - 100,000 |