Radio,Television And Electronic Paper 2, WASSCE (SC), 2016

Question 3.

(a)

  • (i)Name the parts labeled X and Y.
  • (ii)Determine the frequency of the waveform.

(b)An alternating voltage has a peak value of 4.0kV. Calculate its:

  • (i)average value;
  • (ii)r.m.s value.

(c)

(ii) Copy and complete Table 1 by marking with a tick “√” the mode of fault indication for each equipment. The first one has been done for you.

(i)List any three electronic measuring instruments.

Fault finding equipment

Visual indication

Audio indication

Tester

              

 

Logic probe

 

 

TV analyzer

 

 

Signal tracer

 

 

Oscilloscope

 

 

 

Observation

The expected answers were:

  1. (i) X – Period;
    Y – Amplitude

(b) Using the Kirchhoff’s Current Law:

(i)Vavg = 0.637Vpeak

    = 0.637 x 4000    

    = 2,548V.

(ii)

(c)

(i) Electronic measuring instruments

• Ammeter

• Ohmmeter

• Voltmeter

• Multimeter

• Oscilloscope

(ii) Fault finding equipment and mode of fault indication


Fault finding equipment

Visual indication

Audio indication

Logic probe

 

Signal tracer

 

              

TV analyzer

                                  

 

Oscilloscope

                 

 

Many candidates did not show an understanding of the relationship between Vpeak, Vavg and Vr.m.s. . More so, candidates did not show good understanding of the mode of fault indication of fault finding equipment.