CATHODE RAY TUBE 



tetrode cathode ray tube, with a second anode potential of 10 kV, the 

 deflection sensitivity is one in. per volt. Each deflector coil comprises two 

 windings, A and B, fed from the two sides of the output stage. Each of the 

 4 windings consists of 200 turns of No. 34 enamelled wire. The core used in 



+ 300 



Set no- signal output stage 

 anode current to 60mA 



2EL37 

 in parallel 



Gain 

 balance 



150 



2k 

 100W 



-2 EL37 

 in parallel 



Figure 32.39 



Bottom 



the deflector coil assembly comprises two Ferroxcube mouldings, part FX 

 1154, spaced | in. 



Circuits for supplying time-base deflector coils have been discussed in 

 Part I. 



Electronic brightness control of cathode ray tubes 



When photographing a triggered time base it is helpful if the electron 

 beam can be suppressed automatically between sweeps ; otherwise there is a 

 risk of fogging of the record by the relatively bright resting spot. It was 

 pointed out in Part I that the triangular wave generators, such as would be 



467 



