Because there is a vacuum inside the tube (which has to be strong enough to hold out the air), and the tube must be glass for the phosphor to be visible, the tube must be made of thick glass. Changing this picture 30 times every second will make it look like the picture is moving. By carefully controlling which bits of phosphor light up, a bright picture can be made on the front of the vacuum tube. The electrons can be aimed by creating a magnetic field. The electrons make the phosphor light up. The electrons hit the front of the tube, where a phosphor screen is. To better control the direction of the ray, the air is taken out of the tube, making a vacuum. This is used to pull the electrons toward the front of the glass tube, so the electrons shoot out in one direction, making a cathode ray. Also inside the glass tube is an anode that attracts electrons. The cathode is an electrode (a metal that can send out electrons when heated). It was used in almost all computer monitors and televisions until LCD and plasma screens started being used. It was the most common type of display for many years. The cathode ray tube or CRT was invented by Karl Ferdinand Braun. Updated April 03, 2019.Cathode ray tube using electromagnetic focus and deflection (parts shown are not to scale) Is the target for auto advert insertion -!> Thanks to Frank Philipse for supplying the above PDF datasheet. See also 1940 adverts.Ībsolute Maximum Operating Conditions ¶ CRT ![]() Type CV1097 was first introduced in 1940. The end window envelope is 160 mm in diameter, and including the B12D base is 420 mm tall. See also our VCR97 in its original sealed crate. This would often cause a break in a wire that could be repaired by un-screwing the base and re-soldering. A common fault in these tubes was a failure of the cement holding the base to the glass neck. Inside the removable base plate is the evacuation tube and wires that are soldered to the contacts. Correct location of the tube is by means of the keyway. The side contacts mate with flat metal strips in the base. A flat un-laminated faceplate would implode. The 6 inch screen is curved so as to withstand the forces on the glass. The red part of the lead-out wire that passes through the glass can be seen within the centre of the ceramic ring. The ceramic ring is clamped to the pinch stem. This tube is constructed with a ceramic ring to hold the electrodes in place. The pinch is circular with a re-entrant centre section and can be seen just above the base plastic. This leaves the cathode at about 2.5 kV below ground. ![]() The standard practice was to hold the final anode at earth potential or that of the deflection amplifier HT rail. The heater cathode insulation was not designed to withstand high voltages and so the heater supply would be floating. The connection would be to pin 10 as the final anode. The design specification is for A1, A3 and the coating to be tied together and manufacturers could elect to do this at manufacturing stage. Pin 7 is the internal graphite 'Aquadag'coating. ![]() An advert for Premier Radio in Wireless World August, 1948 confirms that the VCR97 is equal to the Mullard ECR60. This may be to connect to the final anode or it could be an early example of post deflection acceleration. The CV2286 is very similar physically but has an EHT connector on the side of the bell. The CV2810 is the same tube but with a short persistence violet phosphor beneath a longer persistence green phosphor. The phosphor type is P1 medium persistence. It was first used in 1940 in the ASV range amplitude display. This 6 inch green phosphor cathode ray tube was designed especially for WWII airborne radar and the prototype was the VCR97. The CV1097 seen here is marked with the stores code 10E/222. Mullard The Liverpool Collection Other CV1097 exhibits
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