The CV2175 is a small three inch electrostatically focused cathode ray tube and the commercial equivalent is the Mullard DG7-5 tube. This was probably used for an oscilloscope type instrument. The phosphor is green and this tube came with different colour options for a range of applications. The screen is 70 mm diameter at its widest.
It is typical of these small oscilloscope tubes that the final anode voltage is of the order of 800 Volts. Normally the final anode is held at + 200 V and the cathode and heater hang 600 V below ground. This arrangement has advantages for driving the deflection plates.
The B9G base with central locating spigot.
The pointed hard pins are directly sealed into the glass foot in this all glass constructed tube.
The tube neck and on the left can be seen the Y deflection plates. The plates closest to the electron gun need the smallest voltage to deflect the beam and are therefore used for the signal voltage. The X plates are hidden behind the aquadag graphite coating on the inside of the bell of the tube.
See alsoCV5171 for another in this family of tubes and DG7-32 for the replacement improved low voltage oscilloscope tube.
The end window envelope is 33 mm in diameter, and excluding the B9G base pins is 140 mm tall.
Reference: Data-sheet. Type CV2175 was first introduced in 1950. See also1950 adverts.
