The 1CP1 is a one inch oscilloscope tube. They were made in large numbers from the early 1950s and were used for transmitter monitors as well as miniature oscilloscopes.
The 1CP1 was made by several manufactures including Cossor, Emitron and Pinnacle. Although delivering the same final specification each make used a different internal construction.
The final anode voltage of 1,000 is the maximum and good results can be achieved with 650 Volts. This can be achieved with a simple voltage doubler from the main HT transformer winding. With much lower a3 voltages the image becomes dim. The sensitivity of the electrostatic deflection is a function of the final anode voltage. For Y sensitivity the formula is 95/a3 mm/Volt. The X formula is 110/a3 mm/Volt.
See the above advert for a typical circuit.
The ceramic spacers hold the electrodes in position and the black coating inside the glass is the final anode.
The Y plates are in the centre of the image.
The end window. The milky getter indicates that the vacuum has failed in this exhibit.
The B8B base.
The end window is 29 mm in diameter and excluding the base pins is 85 mm tall.
References: Data-sheet & Etel Advert. Type 1CP1 was first introduced in 1953. See also1953 adverts.
