Function Generator – Block Diagram, Working Principle & Construction – Electronic Instrumentation

Function Generator – Block Diagram, Working Principle & Construction – Electronic Instrumentation


Do subscribe to Ekeeda channel and press bell icon to get updates about latest Engineering, HSC and IIT-JEE Mains and Advanced videos.Hello Friends,In this video we are going to study about the instrument function generator we will study that what is a function generator what is the use of function generator its block diagram construction and working so let us start with our topic. Function generator we can say in our basic language that it is a type of instrument which is used to generate the different types of wave forms like sinusoidal wave form like triangular wave form rectangular wave form square wave form so different types of wave forms which are having different frequencies they can be generated with the help of this instrument function generator so we can define function generator as a signal source because it is generating the various types of signals so it is a type of signal source which has the capability of producing different types of waveforms as its output signals now the different types of waveforms or the most common waveforms which are generated by this function generator are sign base rectangular waves and triangular waves sawtooth wave you so these types of waveforms are most commonly produced by the function generators now because the function generator it is generating these waveforms so these waveforms should have will have some frequencies so the frequencies of these signals they can be adjusted from few holes to several kilohertz you so we can say that the function generator it is going to produce the waveforms in front in the range from a fraction of holes to several hundred kilo words so in this range it can produce the different waveforms now the function generators they are considered as the most versatile instrument in the electrical and electronics laboratory because the waveforms produced by the function generators they have applications in different areas so because these waveforms they are to be used for various types of application or for a number of applications that is by the function generator they are considered as the most versatile and common instrument found in the laboratories you these waveforms they are used for different types of applications there are also some of the features in function generator which make them it a versatile instrument so let us study these features of function generator the first feature of the function generator is that sorry the first feature of the function generator is that the various waveforms which are produced by the function generator they are available at the same time means if at the same time we want that a sinusoidal waveform and a triangular waveform will be available should be available from the function generator then the function generator it has that feature that it can provide the various types of outputs at the same time so for like for different applications there are two application in one application we want a sinusoidal beam and in another application we want a square wave so at the same time the function generator is capable of providing the two types of outputs so that is the feature of the function generator which makes it a versatile instrument you so if different like if the generator has generated two different signals so these signals can be used for two different applications also let us see some example of this feature that how the various outputs of the generator can be used for different applications the first example is the case that we are providing a square beam and a sawtooth wave at the function generator is providing the square wave and a sawtooth wave at the same time you it is used to drag the horizontal deflection amplifier of an oscilloscope where we are getting the visual display on the screen for the measurements so simultaneously or square wave and a sawtooth wave is provided by the function generator which are used for the two different applications so here you can see that the square wave is used for the linearity measurements in an audio system whereas sawtooth wave is used to provide the is used to drive the horizontal deflection amplifier of an oscilloscope which is giving a visual display for the measurements okay another example of this feature is the generation of a triangular wave and a sine wave okay so triangular wave and sine wave of equal frequencies they can be produced by the function generator you so when a triangular wave and a sine wave of equal frequencies are produced by the function generator such that the zero crossing of both the waves are made to occur at the same time means at the same time both the whales they are crossing the zero point this will be the case when suppose this is our triangular wave and sinusoidal wave having the same frequency both are generated by the function generator so the zero crossing means when the signals they are passing the zero point it is occurring at the same time so ad in that case are linearly varying waveform is available and this waveform it can be started at the point of zero phase of the sine wave now this type of waveforms they can be used for measuring the phase difference between the two signals so this is the application where the function generator is generating two types of waveforms and they are used for the different applications so this was the special feature in the function generator another special feature of function generator is the capability of function generator of phase locking and external signal source you so this is also another feature of the function generator that it has the capability of face locking to an external signal source let us see that how this feature is used in different examples first example is that you now we are having two function generators and both these functions and Raiders are phase locked with each other so these two function generator they will be providing us the two output signals so as these function generators are phase lock so the two output signals we can vary the phase between these two signals by a fixed amount okay like if you want that the two signals they will be having a phase difference of Pi by 2 pi or 3 PI by 2 so we can vary this phase difference by because the two function generators they are face logged with each other so the two output signals they can also be displaced in phase by one adjustable amount if we are varying one signal by PI by two or by some amount we are changing its face so that same amount of phase difference will be face will be produced in the phase change will be produced in the second output signal also ok second example is that you so in the second case one function generator it is phase-locked to a harmonic of the sine wave of another function generator one function generator is providing an output signal another function generator it is providing a sine wave so the harmonic of that sine wave will be phase locked with the first function generator now in that case by the adjustment of the phase and the amplitude of the harmonic you so if we are adjusting the face and the amplitude of that harmonic sine wave almost any way form may be produced any waveform means that any waveform which is the summation of the fundamental frequency which is generated by the one function generator and the harmonic which is generated by the another function generator so the any waveform which is the combination of which is the summation of the fundamental fundamental sine wave and the harmonic sine wave they can be produced so that is the use of this second feature of the function generator another example is that you so when a function generator is phase-locked to an accurate frequency standard and all its output waveform will have the same frequency stability and accuracy as that of the standard so when we are faced locking with the function generator with the standard frequency source so all the characteristics of that standard frequency source will come in to the output waveforms of the function generator so these are the three uses of this special feature of functions on data that it has the phase locking capability to an external signal source whenever an external signal source whatever quality that signal source will have that quality will come in to the output signals of the function generator when the two generators are faced logged with each other so these were the two features of the function generator now let us come to the block diagram of the function generator if we see the block diagram it will be so this is the block diagram of a function generator the various components are here we are having a frequency control network then we are having two constant current supply sources 1 & 2 then we are having an integrator capacitor of voltage comparator multivibrator is there a resistance diode shaping circuit to output amplifiers are there and as the function generator it gives us the waveforms different types of waveforms so here we are having three types of waveforms a square waveform a triangular waveform and a sinusoidal waveform so this is the dock diagram of the function generator let’s study the functions of each of the blocks in this diagram and also studied it’s working now as you said that the function generator it is capable of producing different waveforms in the frequency range from minut fractions of words to several hundred kilo words so how this frequency is controlled in this block diagram in this block diagram they are having the integrator okay we are having an integrator so the frequency is controlled by the magnitude of this current which is driving the indicator okay so we can say that the frequency is controlled by the magnitude of the current that drives the integrator so as in this block diagram we are having two current supply sources so both of these current supply sources they are going to going to vary the frequency of the output signal okay now this function it is providing different types of waveforms three waveforms are their sinusoidal triangular and square wave where we are having the symbol this is for sinusoidal wave triangular we are having this symbol and for square wave we are having the symbol now these three waveforms they are produced in the frequency range of 0.01 to 100 kilo Hertz okay so in this frequency range we can produce the three different types of waveforms now here in this block diagram we are having a frequency control network so this frequency controlled network it is going to control the frequency and here on the front panel of the function generator we are having a knob which is called the frequency control and by varying this or moving this knob we can can we can change the frequency of these output waveforms so here we are having a frequency control neck which is governed by the dial which is present on the front panel of the instrument also here we are having an external frequency control also so this external frequency control can also go the one this frequency control network so first part is the frequency control network in the block data this frequency control network either it is governed by the frequency dial on the front panel of the instrument or it can be governed by an external frequency control now the second part is that because this frequency control Network it is providing the frequency control voltage so this frequency control voltage coming out of this control network it is going to regulate the two current sources you can see we are having the supply source 1 & 2 written over here so this current source it is going to supply a constant current to this integrator whose output voltage is going to increase linearly with the time whereas this lower current source it is going to provide the voltage which is going to change the output voltage of the integrator which is going to decrease linearly with time so due to this current source the output voltage of the integrator is increasing linearly with time whereas due to this curve the second current source that is lower current source the output voltage of the integrator it is decreasing linearly with time so the upper current source it supplies a constant current to the integrator whose output voltage is going to increase linearly with this output voltage will be e out equals to minus of 1 upon C integration I D think ok this is the output voltage of the integrator due to the upper current source now any increase or decrease in this current it is going to change the slope of the output voltage because this upper current source which is supplying a constant current to this integrator so if there is any change in the in this current so the slope of the output voltage of the integrator that is also going to change okay now this was due to the upper current source now comes the lower current source now the lower current source it supplies a reverse current to the integrator okay and you to the silvers current the output voltage of the integrator it decreases linearly with time okay so if we see that due to the upper current source the output voltage it is increasingly in earlier time means it will be in this way as the time is increasing it is also increasing linearly with the time due to the lower current source which is providing a reverse current the output voltage is decreasing linearly with time so it is going to decrease in this way again it is going to increase linearly with time so thus increasing voltage will come again decreasing voltage so in this way we are getting a triangular wave okay so you can see that the output of the integrator it is directly the triangular wave now for the square wave what the voltage comparator multivibrator is connected here so this when the output voltage of this first the the current source it is providing the voltage which is increasing linearly with time here it is increasing linearly with time now when the voltage it has attained a predetermined value on the positive slope this integrator output voltage it is going to terminate okay and this will become constant then after that due to this lower current source again the decrease in voltage is going to come and then it has come to a predetermined level on the negative slope of the output waveform the voltage comparator it is again going to changes its state and it is going to switch on to the current supplies so this voltage comparator and multivibrator it is going to decide or it due to this comparator the output waveform which is a square wave that is produced so what the voltage comparator multivibrator does when this current source is providing the current which is increasing linearly with time so event this has come to a predetermined value it is going to cut off the supply and this supply will be connected to the constant current source in the negative side if it has achieved a predetermined value again it is going to change the state by switching on and off this switch okay so with the help of this switch and voltage comparator our square wave is produced from a triangular base you so the comparator is going to produce a square wave which is having the same frequency as that of the output of the integrator now comes the sinusoidal D so for sinusoidal de we have the resistance diode shaping circuit in the block diagram and this circuit is going to change the slope of the triangular wave so that it will be converted into a sinusoidal wave you so you can see that the output the output of the integrator it’s basically a triangular wave which is converted into a square wave by the comparator and into a sinusoidal wave by the resistance diode Network okay so in this way the three types of wave forms which are having different frequencies they are produced by the function generator the shape of the waveform will be decided that which socket is being used and the frequency is decided by the frequency control Network so different waveforms which are having frequencies in the range from 0.01 watts to 100 kilohertz they are produced by the function generator so this was the block diagram and the working of the function generator the applications of the function generator we can say that wherever we need that different types of waveforms are to be supplied in our circuit in an electrical and electronic circuit we can use the function generator now if we want to display the wave form of this function generator be if you want to see that waveform this function generator is given as an input to the CR rose that is cathode ray oscilloscope so the waveform that is either square wave sine wave or triangular wave they are displayed on the screen of the cathode ray oscilloscope so if you want to measure the frequency that what is the frequency of these waveforms what is the time period amplitude that can be done with the help of the C aru’s so in conjunction or in in with the help of the CRS and the function generators the signals are provided in the electronic and the electrical laboratories so that is the main application of the function generators so in this video we studied that what is a function generator what are the special features in the function generator which makes it so versatile instrument then we studied the block diagram and the working of the function generator so I go that this topic function generator it is now clear to you thank you

41 Replies to “Function Generator – Block Diagram, Working Principle & Construction – Electronic Instrumentation”

  1. Please use preprepared notes. I don't think anyone wants to see you writing. It is a waste of time for those who are watching the video

  2. Need some improvent in the lecture. lecture was good but it too lengthy,
    Important and needed thing only need to put in that..
    Keep doing mam

  3. Hello Friends,

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  4. Hindi mai bol. Lau bhenchodd… Aur ye kaise padha rahi hai attenuation is something that attenuates signal?????…. Bhag bc

  5. U said that various outputs can be available at same time. Is it possible. I think that the function generator has single output where we select the shape of signal

  6. Your videos helped to prepare for an important psc exam for me. Rare topics. Explained well with perfect block diagrams. Thank you ma'am for your classes.

  7. Mam your lecture is too long… Please make small video like 10-15 min and app notes phele se hi likh kr likh lijiye..aise bhot time Bach jayega

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