| Description | The X79 is a triode hexode frequency changer or mixer. The triode control grid is connected internally to the oscillator injection grid (g3) of the hexode. |
| Manufacturer | Marconi |
| Country of Origin | * |
| Introduction Year | 1950 |
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| Description | The W77 is a miniature variable μ pentode designed to operate at HF. This suggests radio frequency amplifiers as well as intermediate frequency amplifiers. |
| Manufacturer | |
| Country of Origin | England |
| Introduction Year | 1949 |
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| Description | The 6F18 is a variable μ HF pentode for use in broadcast receivers at HF or IF. |
| Manufacturer | GEC |
| Country of Origin | England |
| Introduction Year | 1956 |
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| Description | The UBC81 small double diode triode was designed for signal demodulation and AGC detection in universal mains domestic equipment. The triode section could be used for a first stage of amplification after the detection process. |
| Manufacturer | Philips Miniwatt BEL |
| Country of Origin | Holland
India |
| Introduction Year | 1954 |
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| Description | The U10 directly heated full wave rectifier has an internal coating on the upper part of the envelope. A close look shows that the valve has cathode tubes that are internally strapped to one side of the filament. Our other classic enveloped U10 has a hairpin of oxide coated ribbon as the emissive surface. The original U10 came with a balloon envelope.The maximum reservoir capacitor is not quoted, but at 60 mA maximum output current the U10 was clearly designed for broadcast radio reception in 1930s all mains sets. The 4.0 Volt heater is characteristic of the 1930s British heater standard. |
| Manufacturer | * |
| Country of Origin | * |
| Introduction Year | 1930 |
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| Description | The EZ80 full wave rectifier was found in many broadcast receivers and domestic audio equipment.Suited to the task, at 90 mA maximum current and with a required series resistance of 300 ohms to reduce the initial surge in charging the maximum 50 µF reservoir capacitor, each anode would conduct in turn when connected to either end of a grounded centre tapped mains transformer. The EZ81 is pin compatible but rated at 160 mA.The anodes are mounted vertically and at right angles over a common cathode. The anodes are identical but one is mounted upside down so they both fir the cathode. The anodes form a cross to give maximum area for heat dissipation. |
| Manufacturer | BEL |
| Country of Origin | India |
| Introduction Year | 1954 |
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| Description | Mullard describe the EF41 as a variable μ RF pentode for use as an RF or IF amplifier. In the literature Mullard state that although pins 3, 4 and 7 are internally connected together, it is recommended that the external cathode connection be made to pin 7 as this point offers the lowest connection inductance. |
| Manufacturer | Philips Miniwatt Telefunken |
| Country of Origin | Britain
* |
| Introduction Year | 1947 |
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| Description | The EBF89 features two signal diodes and a variable μ pentode in the one envelope and sharing a common cathode. The diode anodes are small plates placed either side of an extended cathode tube.The variable μ characteristic is indicative of a device designed to have its gain controlled by an AGC system. This places this valve in service as a final IF amplifier and detector. The high impedance of the pentode supports the case for use with a tuned circuit connected to the anode. |
| Manufacturer | BEL |
| Country of Origin | India |
| Introduction Year | 1958 |
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| Description | The DY802 is an EHT rectifier for monochrome TV service as colour television tubes usually required 25 kV EHT.The 1.4 Volt heater was designed to be run from a winding on the transformer supplying the EHT. This would be an HF transformer similar to the line output transformer of a television receiver. The DY802 is designed for a maximum PIV of 30,000 Volts and will produce an output voltage of 20,000 Volts. The maximum reservoir capacitor is 0.003 μF.The anode bell contains the indirectly heated cathode. |
| Manufacturer | BEL |
| Country of Origin | India |
| Introduction Year | 1965 |
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