Basic Electronics Paper 2, WASSCE (PC), 2016

Question 1

            

  1. Sketch the frequency determining circuit of the following oscillators:

(i) an LC oscillator;
(ii) an RC oscillator.

            (b) List two:
(i) LC oscillators;
(ii) RC oscillators.
The requirement here is that of showing the frequency determining circuits of LC and  
RC  oscillators.

 

The expected answers were:

           (a)         (i)         LC oscillators                                   

 



(ii)           RC oscillators   



(b)  (i)         LC oscillators
-  Tuned collector oscillator
-  Hartley oscillator
-  Colpitts oscillator

(ii)        RC oscillators

  • Phase shift oscillators
  • Wien bridge oscillators
  • Multivibrators
  • -Twin Tee                    
    No candidate gave the required diagram, only a very few listed some of the
    oscillators.