12-08-2023, 06:38 PM
Many thanks Bill for the tube information. I see the tube has the usual X and Y plates and that the central electrode is used to deflect the spot along the radius of a circular trace. The circular trace is obtained in the usual manner using 90 degree phase shift circuits as shown in the data sheet. Armed with the part number I have found some more information here https://www.radiomuseum.org/tubes/tube_3dp1.html including some images of a circular trace modified in this way. With a bit of luck one of the old wartime display units will find me one day... Very nice, For no particular reason I've attached a couple of pictures from my own oscilloscope toying. David.
