Answer MET Question 42

Question: A. Explain what is meant by the terms wave form, frequency and average value. 

Answer: Wave form: It is the shape of Current, Power or Voltage vs Time curve. for example sine wave, half-wave rectified sine wave, full-wave rectified sine wave, square wave, triangle waveform or saw tooth waveform etc.

Frequency :Alternating current (ac) frequency is the number of cycles per second in an ac sine wave. Frequency is the rate at which current changes direction per second. It is measured in hertz (Hz), an international unit of measure where 1 hertz is equal to 1 cycle per second

Average Value: The average of all the instantaneous values of an alternating voltage and currents over one complete cycle is called Average Value. If we consider symmetrical waves like sinusoidal current or voltage waveform, the positive half cycle will be exactly equal to the negative half cycle. Therefore, the average value over a complete cycle will be zero. The work is done by both, positive and negative cycle and hence the average value is determined without considering the signs. So, the only positive half cycle is considered to determine the average value of alternating quantities of sinusoidal waves.