VG-237 tube

A rather monstrous mercury gastron. Oxide cathode, directly heated. Old name - VG7. Electrical parameters Filament voltage - 5 V Filament current - 22 A Ignition voltage - 25 V Maximum average rectified current - 3.5 A Maximum pulse rectified current - 10 A Voltage drop - 16 V Maximum permissible reverse voltage amplitude - 10000 V Warm-up time in operation - 5 minutes Warm-up time after storage - 1.5 hours Service life - 2000 hours Manufacturer - Ryazan Electronic Devices Plant. The directly heated cathode is made in the form of a corrugated tape, rolled into a spiral; corrugation achieves an increase in the active surface of the cathode by 1.5-2 times. The distance between the turns of the cathode spiral is chosen for reasons of ensuring, on the one hand, plasma access to the entire oxidized surface of the tape (which requires sufficient gaps between the turns of the spiral), and on the other hand, obtaining the required heating temperature of the cathode while spending a minimum of power in the filament circuit (which requires closer proximity of the turns of the spiral to each other). In order to protect the cathode neck from direct exposure to a flow of radiant energy, a heat screen is installed below the cathode. The anode is made in the form of a hollow nickel bowl. The advantage of a hollow anode is its relatively larger receiving surface and the ability to cover the upper part of the cathode assembly (semi-closed design). This makes it possible to bring the anode and cathode as close as possible and obtain a small volume of plasma and a negative potential drop at the anode. At the same time, both the deionization time and the reverse current are shorter, which, other things being equal, makes it possible to achieve higher values of reverse voltages withstand by the device. The disadvantage that appears simultaneously with the indicated positive factors of influence from the proximity of the anode to the cathode, which consists in an increase in the share of power transmitted through radiation from the cathode to the anode, is mitigated by the fact that the radiative surface of the anode is chosen to be large enough. A crooked anode “cover” is not a defect, it is so!