# Function Generator

Function Generator or sometimes called a Waveform Generator is a device or circuit that produces a variety of different waveform at a desired frequency. It can generate Sine waves, Square waves, Triangular and Sawtooth waveform as well as other types of output waveform.

There are many “off-the-shelf” waveform generator IC’s available and all can be incorporated into a circuit to produce the different periodic waveform required.

**Waveform Generator IC**

**Using 8038**

**Periodic Waveforms:**

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Periodic waveform are the most common of all the electrical waveform as it includes Sine Waves. 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.

**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. Common uni-directional waveforms include Square-wave timing signals, Clock pulses and Trigger pulses.

**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. Bi-directional waveforms go through periodic changes in amplitude, with the most common by far being the Sine-wave.

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:

**Period: –**This is the length of time in seconds that the waveform takes to repeat itself from start to finish. This value can also be called the*Periodic Time*, ( T ) of the waveform for sine waves, or the*Pulse Width*for square waves.

**Frequency: –**This is the number of times the waveform repeats itself within a one second time period. Frequency is the reciprocal of the time period, ( ƒ = 1/T ) with the standard unit of frequency being the*Hertz*, (Hz).

**Amplitude: –**This is the magnitude or intensity of the signal waveform measured in volts or amps.

**Periodic Waveforms:**

** **

Periodic waveforms are the most common of all the electrical waveforms as it includes Sine Waves. 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.

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. In other words, the time it takes for the waveform to repeat itself.

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. For example, a sinusoidal waveform which takes one second to complete its cycle will have a periodic time of one second. Likewise a sine wave which takes five seconds to complete will have a periodic time of five seconds and so on.

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.

**A Sine Wave Waveform**

Units of periodic time, ( T ) include: Seconds ( s ), milliseconds ( ms ) and microseconds ( μs ).

For 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 360o ( T = 360o ) or in Radians as 2pi, 2π ( T = 2π ), then we can say that 2π radians = 360o – ( Remember this! ).

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. 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). Then Hertz can also be defined as “cycles per second” (cps) and 1Hz is exactly equal to 1 cycle per second.

**Square Wave Electrical Waveforms**

Square-wave Waveforms are used extensively in electronic and micro electronic circuits for clock and timing control signals as they are symmetrical waveforms of equal and square duration representing each half of a cycle and nearly all digital logic circuits use square wave waveforms on their input and output gates.

**A Square Wave Waveform**

We know that square shaped electrical waveforms are symmetrical in shape as each half of the cycle is identical, so the time that the pulse width is positive must be equal to the time that the pulse width is negative or zero. When square wave waveforms are used as “clock” signals in digital circuits the time of the positive pulse width is known as the “Duty Cycle” of the period.

**Applications of functional wave generator mainly involves in the following**

- In the development and research
- Electrical and electronic equipment repair business
- In the Electronic hobbyists
- It is used in the many educational institutions
- Response or stimulus testing, frequency response characterization
- In the circuit signal injection.