Uploaded December 2021 | Updated September 2026, 3 weeks ago
Short video on old indicator tubes from valve equipment. Three common types are shown operating with a low frequency sine wave modulating the grids. Fluorescent coatings are used with in the tube to produce a visual indication for signal level. Had some issues with sound on this video, apologies it's a little worse than usual. The three tubes here are electrically very similar but due to the pin arrangements are not interchangeable.
Short video on old indicator tubes from valve equipment. Three common types are shown operating with a low frequency sine wave modulating the grids. Fluorescent coatings are used with in the tube to produce a visual indication for signal level. Had some issues with sound on this video, apologies it's a little worse than usual. The three tubes here are electrically very similar but due to the pin arrangements are not interchangeable.
