Basic Electronics Paper 2, May/June 2015

Question 1

  1. State one difference between analogue and digital multimeter.
  2. List two examples of an analogue meter.
  3. State the function of the following controls used in the cathode ray oscilloscope (CRO):
  4. Focus;
    1. Y-shift;



The expected answers were:
(a)        (i)   Analogue meter  -  Moving scale read out. (or pointer movement)
            (ii)  Digital meter  -  Digital/Numerical read-out. (or numerical display)                   
(b)        Any two examples:
            -  Moving coil instrument
            -  Moving iron instrument                              
            -  Electrostatic instrument
            -  Thermocouple instrument                                                               
(c)        (i)         FOCUS CONTROL  -  It adjusts the spot or trace for a sharp image.
                                                                        (Sharpens beam)                     

            (ii)        Y-SHIFT  -  It moves the spot or trace up or down.             
(Vertical movement of spot)

            (iii)       X- SHIFT  -  It moves the spot or trace to the left or right.  
(horizontal movement of sport)

Majority of the candidates responded correctly to the question but it is apparent that they were not exposed to other notable differences such as: higher frequency range; constant internal resistance and better accuracy for the digital meter. Responses to the question on the function of controls of the CRO were very well responded to.