| GENERAL DESCRIPTION |
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The 891-R is a three-electrode tube for use as a radio-frequency power amplifier, oscillator, Class A modulator, and Class B modulator. The construction of the filament permits operation from two-phase or single-phase alternating current, as well as from direct current, for all classes of service. The plate of the 891-R is air-cooled by means of a special radiator which is fitted to the tube by the manufacturer. The plate is capable of dissipating 4 kilowatts of power, depending on the service in which the tube is used. The 891-R can be operated at maximum ratings at frequencies as high as 1.6 megacycles and up to 20 megacycles at reduced ratings. |
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| TECHNICAL SPECIFICATIONS | |
| ELECTRICAL | |
| Filament Excitation Voltage per Section Current Starting Current Cold Resistance |
Tungsten: Two-Section Type Single- or Two-Phase AC, or DC 11 volts 60 amp The filament current should never exceed 120 amperes, even momentarily. 0.031 ohm |
| Amplification Factor | 8.5 |
| Direct Interelectrode Capacitances (Approx.) Grid to Plate Grid to Filament Plate to Filament |
28 μμF 19 μμF 2.5 μμF |
| MECHANICAL | |
| Mounting Position | Vertical, Filament End Up |
| Maximum Overall Length | 22" |
| Maximum Radius | 6-½" |
| Radiator | Integral Part of Tube |
| Incoming Air Temperature | 45 max. °C |
| Radiator Temperature | 180 max. °C |
| Bulb Temperature | 150 max. °C |
| Specifications may change without notice | |
| THIS TUBE IS USED IN THE FOLLOWING SHORTWAVE BROADCAST TRANSMITTERS | ||
| Manufacturer | Transmitter specifications | Power in kW |
| RCA | ET-4750 | 7.5 |
| THIS TUBE IS AVAILABLE FROM | ||
| Manufacturer | Rebuilder | Distributor |
| Kennetron | ||
| 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 |