If we take the reciprocal of the period, ( 1/T ) we end up with a value that denotes the number of times a period or cycle repeats itself in one second or cycles per second, and this is commonly known as Frequency with units of Hertz, (Hz). We now know that the time it takes for electrical waveforms to repeat themselves is known as the periodic time or period which represents a fixed amount of time.
BIPOLAR SQUARE WAVE MATHEMATICAL REPRESENTATION FULL
Units of periodic time, ( T ) include: Seconds ( s ), milliseconds ( ms ) and microseconds ( μs ).įor sine wave waveforms only, we can also express the periodic time of the waveform in either degrees or radians, as one full cycle is equal to 360 o ( T = 360 o ) or in Radians as 2pi, 2π ( T = 2π ), then we can say that 2π radians = 360 o – ( Remember this! ). So, if the length of time it takes for the waveform to complete one full pattern or cycle before it repeats itself is known as the “period of the wave” and is measured in seconds, we can then express the waveform as a period number per second denoted by the letter T as shown below. Likewise a sine wave which takes five seconds to complete will have a periodic time of five seconds and so on. For example, a sinusoidal waveform which takes one second to complete its cycle will have a periodic time of one second. Then this period can vary with each waveform from fractions of a second to thousands of seconds as it depends upon the frequency of the waveform. In other words, the time it takes for the waveform to repeat itself. The amount of time it takes between each individual repetition or cycle of a sinusoidal waveform is known as its “periodic time” or simply the Period of the waveform. The AC (Alternating Current) mains waveform in your home is a sine wave and one which constantly alternates between a maximum value and a minimum value over time. Periodic waveforms are the most common of all the electrical waveforms as it includes Sine Waves.
Amplitude: – This is the magnitude or intensity of the signal waveform measured in volts or amps.Frequency is the reciprocal of the time period, ( ƒ = 1/T ) with the standard unit of frequency being the Hertz, (Hz). Frequency: – This is the number of times the waveform repeats itself within a one second time period.This value can also be called the Periodic Time, ( T ) of the waveform for sine waves, or the Pulse Width for square waves. Period: – This is the length of time in seconds that the waveform takes to repeat itself from start to finish.Whether the waveform is uni-directional, bi-directional, periodic, non-periodic, symmetrical, non-symmetrical, simple or complex, all electrical waveforms include the following three common characteristics: Bi-directional waveforms go through periodic changes in amplitude, with the most common by far being the Sine-wave. Bi-directional Waveforms – these electrical waveforms are also called alternating waveforms as they alternate from a positive direction to a negative direction constantly crossing the zero axis point. Common uni-directional waveforms include Square-wave timing signals, Clock pulses and Trigger pulses. Uni-directional Waveforms – these electrical waveforms are always positive or negative in nature flowing in one forward direction only as they do not cross the zero axis point. There are many different types of electrical waveforms available but generally they can all be broken down into two distinctive groups.
In plain English this means that if we plotted these voltage or current variations on a piece of graph paper against a base (x-axis) of time, ( t ) the resulting plot or drawing would represent the shape of a Waveform as shown. Technically speaking, Electrical Waveforms are basically visual representations of the variation of a voltage or current over time. However, before we can begin to look at how the different types of waveforms are produced, we firstly need to understand the basic characteristics that make up Electrical Waveforms. These types of signal waveform can then be used for either timing signals, clock signals or as trigger pulses. But sometimes in electronic circuits we need to produce many different types, frequencies and shapes of Signal Waveforms such as Square Waves, Rectangular Waves, Triangular Waves, Sawtoothed Waveforms and a variety of pulses and spikes.
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