Question 1
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(a) State two causes of electric shock in a Radio, Television and Electronic Works (RTV) workshop.
(b) Identify the following safety signs in a Radio, Television and Electronic Works
(i)(i) Identify the circuits represented with the blocks labeled I, II and III.
(ii)(ii) State one function each of blocks I and II.
Observation
The expected answers were:
(a) Causes of electric shock in a Radio, Television and Electronic Works workshop
(b)
- (i) High voltage;
- (ii) Demolition/Men at Work/Hazards/Warning;
- (iii) Poison/Danger/Deadly situation.
I – RF tuner (accept RF amplifier [1 mark] )
II – Audio amplifier
III – Video amplifier
(c)(i)
(ii)
I – (i) selects the desired channel frequency band and converts it to common IF band frequency;
(ii) amplifies the selected signal.
II– magnifies/increases/improves the amplitude/output of audio signal.
Many candidates were unable to identify the circuits represented in the block diagram of the black and white TV receiver and state their functions accordingly.