24-11-2023, 11:35 AM
(This post was last modified: 24-11-2023, 11:45 AM by Mike Watterson.)
I think Amateur radio transmitter power supplies are pretty scary. One for a modest 80W average transmitter might be 450V to 500V at 500 mA, with big smoothing caps. A 1KW RF out might use a 2.2kW PSU at over 2600V, so likely can do 850mA continuously at 2600V. My cheap Lidl DMM died in a blue flash on 750V range attempting to measure approximately 460V HT. A traditional AVO was used after that for anything more than 250V.
Though the old valved colour TVs with X-Ray warning and PD500 across the 25 kV looked scary. I worked one once and abandoned it. It was old ex-Rental in 1973 or 1974. http://www.r-type.org/exhib/aah0027.htm
Designing and testing EHT PSU for TWTs on satellites must be "interesting". Testing trays of 1nF 100 kV capacitors (or maybe 50 kV) for Harrier head-up displays (projection CRTs?) was challenging. Due to piezo effect a quick discharge wasn't enough. You had to leave a resistor across the tray for a while.
TWTs and microwave oven magnetrons are now the bulk of vacuum tube sales. The VFD panels (essentially direct filament triodes) are a long way behind in sales volume and use very modest HT.
Though the old valved colour TVs with X-Ray warning and PD500 across the 25 kV looked scary. I worked one once and abandoned it. It was old ex-Rental in 1973 or 1974. http://www.r-type.org/exhib/aah0027.htm
Designing and testing EHT PSU for TWTs on satellites must be "interesting". Testing trays of 1nF 100 kV capacitors (or maybe 50 kV) for Harrier head-up displays (projection CRTs?) was challenging. Due to piezo effect a quick discharge wasn't enough. You had to leave a resistor across the tray for a while.
TWTs and microwave oven magnetrons are now the bulk of vacuum tube sales. The VFD panels (essentially direct filament triodes) are a long way behind in sales volume and use very modest HT.
