Radio,Television And Electronic Paper 2, WASSCE (SC), 2022

Question 5

 

 

  1.       Classify the following television receiver controls into operating and service controls in

Table 3.


volume control
brightness control
ON-OFF switch
tone selector
height control
horizontal hold control
AGC control
vertical linearity control
fine tuning control
contrast control
channel selector
width control


     Table 3


Operating control

Service control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1.    
  2.    Fig. 3 is a chart of additive colour mixing used in television receivers. Name the colours

in the pat labelled W, X, Y and Z.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W:_______________________________     X:_______________________________

Y:_______________________________      Z:_______________________________

  1.       To produce the colours given in 5(b). the picture tube of a colour television receiver

possesses some components. State:

  1. Three components mounted on the neck of the picture tube;
  2. Two components within the picture tube.

 

Observation

  The expected responses were:

                                                     Table 3


Operating control

Service control

Volume control

AGC control

Tone selector

Height control

Contrast control

Vertical linearity control

Brightness control

Width control

Channel selector

Horizontal hold control

On-off switch

 

Fine tuning control

 

 
(b)  Colours of the labelled parts in Fig. 3
W: Red
X: Blue
Y: Green
Z: White
                                          
(c)  (i)  Components mounted on the neck of the picture tube

  • Deflection yoke assembly
  • Convergence yoke assembly
  • Centering magnet
  • Pin cushing error magnet                                     

(ii) Components within the picture tube

  • Colour Adder
  • Colour Matrix
  • Electron guns
  • Deflection plates
  • Phosphorescent (material) screen
  • Focus screen

.
The reported stated that question 5 was unpopular among candidates as only a few of them attempted it.