Electronics Voltmeters,Ammeters and Ohmmeters are use Amplifiers,Rectifiers and other ancillary circuit to produce a current proportional to the quantity being measured.
This current is measured by PMMC (Permanent magnetic moving Coil) instrument.
This is Analog type instrument.Now an Electronic Instruments are use Digital read out systems and in that case they are called "Digital Electronic Instruments".Till then,the Analog type of instruments are in use because of the economic considerations.
Also Analog and Digital instruments must perform the same functions i.e. measurement of Voltage,Current,Power and Circuit Parameters.The principle operation is different in each case.
Advantages of Digital Instruments:-
01)The Digital Instruments indicate the reading directly in Decimal numbers and therefore errors on account of human factors like due to parallax and approximation are eliminated.
02)The reading may be carried to any number of significant figures by merely positioning the decimal point.
03)Since the output of Digital instruments are in Digital form,the output may be directly fed into memory devices like Tape Recorders,Printers and Digital computers etc. for storage and future computations.
04)The power requirement of Digital Instruments are considerably less.
Tuesday, May 27, 2008
Friday, May 23, 2008
What is the use of TRANSDUCER in Electronic circuits?
An Electronic instrumentation system consists numbers of components to perform a measurement and record its result.Now a days a generalized measurement system consists of Three major components.
01) An input device
02) A signal conditioning or processing device
03) An output device
The input device receives the measure and/or the quantity under measurement and delivers a proportional or analogous electrical signal to the signal conditioning device.Here the signal is amplified,attenuated,filtered,modulated or otherwise modified in format acceptable to the output device.
The input quantity for most instrumentation systems is a "non-electrical quantity".In order to use electrical methods and techniques for measurement,manipulation or control,the non-electrical quantity is generally converted into an electrical form by a device called a "Tranducer"
We can define a Tranducer as a device which,when actuated transforms energy from one form to another.
The broad definition of a Transducer includes,for example device which convert Mechanical Force into an Electric Signal.These device form a very large and important group of Transducers commonly used in industrial instrumentation area.The Instrumentation Engineers and Technologist are therefore primarily concerned with this area of instrumentation.Many other physical parameters,such as heat,intensity of light,flow rate,liquid level,humidity and PH value may also be covered into electrical form by means of Transducers.These Transducers provide an output signal when stimulated by a Mechanical or non-mechanical input.A photoconductor converts a Thermocouple,converts heat energy into electrical voltage,a force produces a change of resistance in a strain gauge,an acceleration produces a voltage in a Piezo-electrical crystal and so on.In all cases,however,the electrical output is measured by standard methods,giving the magnitude of the input quantity in terms of a analogous output.
ELECTRIC TRANSDUCERS
The art of electrical measurements has been mainly used for measurement of electrical quantities but its value in making measurements of non-electrical quantities in this new era of Automation is rapidly growing.In order to measure non-electrical quantities a detector is used which usually converts the physical quantity into a displacement.
This displacement actuates an Electric Transducers,which acting as a secondary Transducer gives an output that is electrical in nature.The Electrical quantity so produce is measured by standard methods used for electrical measurements.The result (Electrical output) gives the magnitude of the physical quantity or condition being measured.
The electrical signal may be a current or a voltage or a frequency and production of these signals is based upon electrical effects which may be resistive,capacitive,inductive etc.. in nature.
The first stage of a system may be simply be called a Transducer stage instead of detector Transducer stage by redefining a Transducer.
A Transducer,in general form,may be defined as a device which converts energy from one form to another.However this definition has to be restricted many times especially in the field of electrical instrumentation.
Keeping this restriction in view,a Transducer may be defined as a device which convert a physical quantity or physical condition into an electrical signal.
01) An input device
02) A signal conditioning or processing device
03) An output device
The input device receives the measure and/or the quantity under measurement and delivers a proportional or analogous electrical signal to the signal conditioning device.Here the signal is amplified,attenuated,filtered,modulated or otherwise modified in format acceptable to the output device.
The input quantity for most instrumentation systems is a "non-electrical quantity".In order to use electrical methods and techniques for measurement,manipulation or control,the non-electrical quantity is generally converted into an electrical form by a device called a "Tranducer"
We can define a Tranducer as a device which,when actuated transforms energy from one form to another.
The broad definition of a Transducer includes,for example device which convert Mechanical Force into an Electric Signal.These device form a very large and important group of Transducers commonly used in industrial instrumentation area.The Instrumentation Engineers and Technologist are therefore primarily concerned with this area of instrumentation.Many other physical parameters,such as heat,intensity of light,flow rate,liquid level,humidity and PH value may also be covered into electrical form by means of Transducers.These Transducers provide an output signal when stimulated by a Mechanical or non-mechanical input.A photoconductor converts a Thermocouple,converts heat energy into electrical voltage,a force produces a change of resistance in a strain gauge,an acceleration produces a voltage in a Piezo-electrical crystal and so on.In all cases,however,the electrical output is measured by standard methods,giving the magnitude of the input quantity in terms of a analogous output.
ELECTRIC TRANSDUCERS
The art of electrical measurements has been mainly used for measurement of electrical quantities but its value in making measurements of non-electrical quantities in this new era of Automation is rapidly growing.In order to measure non-electrical quantities a detector is used which usually converts the physical quantity into a displacement.
This displacement actuates an Electric Transducers,which acting as a secondary Transducer gives an output that is electrical in nature.The Electrical quantity so produce is measured by standard methods used for electrical measurements.The result (Electrical output) gives the magnitude of the physical quantity or condition being measured.
The electrical signal may be a current or a voltage or a frequency and production of these signals is based upon electrical effects which may be resistive,capacitive,inductive etc.. in nature.
The first stage of a system may be simply be called a Transducer stage instead of detector Transducer stage by redefining a Transducer.
A Transducer,in general form,may be defined as a device which converts energy from one form to another.However this definition has to be restricted many times especially in the field of electrical instrumentation.
Keeping this restriction in view,a Transducer may be defined as a device which convert a physical quantity or physical condition into an electrical signal.
Wednesday, May 21, 2008
Deatils about Cathode Ray Oscilloscope.(CRO)
Generally many people known about Cathode Ray Oscilloscope (CRO).Because the CRO is a very useful and versatile laboratory instrument used for display,measurement and analysis of waveforms and other phenomena in electrical and electronics circuit.
No other instrument used in electronics industries is as versatile as the Cathode Ray Oscilloscope.It is widely used for trouble shooting of radio and television receivers as well as for laboratory work involving research and design.
With an Oscilloscope,the wave shape of a signal can be studied with respect to amplitude distirtion and deviation from the normal.Also we can measure voltage,frequency and phase shift by using an Oscilloscope.
The normal form of Cathode Ray Oscilloscope uses a horizontal input voltage which is an internally generated ramp voltage called "Time Base".This horizontal voltage moves the luminous spot periodically in a horizontal direction from left to right over the display area or screen.The vertical input to the CRO is the voltage under investigation.The vertical input voltage moves the luminous spot up and down in accordance with the instantaneous value of voltage.The luminous spot thus the traces the waveform of the input voltage with respect to time.When the input voltage repeats itself at a fast rate,the trace (Display) on the screen appears stationary on the screen.The Cathode Ray Oscilloscope thus provides a means of showing(Visualizing) time varying voltage.As such,the CRO has become a universal tool in all kinds of electric and electronics investigations.
Cathode Ray Oscilloscope operate on voltage.However,it is possible to convert current,strain,acceleration,pressure and other physical quantities into voltage with the help of transducers and thus to present visual representations of a wide variety of dynamic phenomena on CRO.
CRO are also used to investigate waveforms,transient phenomena,and other time varying quantities from a very low frequency range to the radio frequencies.
Oscilloscope have been evolved continuously,and they are now available which can measure frequencies upto 1 Giga hertz and observer events as small as 20 hertz. in duration.
Many additional features are available with some Oscilloscopes and these are includes built in Digital multimeters and Counters.
The Oscilloscopes are progressively getting smarter,and many are Microprocessor controlled.They have the ability to calculate several features such as rise time or pulse width of the measured waveform,and to display these values along with the display of the waveforms.They are easier to use and internal routines often act as a guide for the user,and display a warning if there is any error in setting.
Although,most Oscilloscope are monochromatics,colour Oscilloscope are finding increasing applications in computers and television.
The application of Oscilloscope have been enhanced on account of many recent developments.Most present days Oscilloscope are capable of accepting two or more inputs displaying them simultaneously.
This may be achieved through,using a split beam or by using a multiple beam tube.Sampling Oscilloscope are used for high speed applications.These Oscilloscope employ time sampling through and through their use it is possible to measure signals of about 20 Giga hertz.They can only detect a repetitive waveform and work on the principle of taking sample once every cycle,over several cycles,each sample point being shifted from the previous point.The complete picture of the waveform is stored and can displayed as a stationary signal.
No other instrument used in electronics industries is as versatile as the Cathode Ray Oscilloscope.It is widely used for trouble shooting of radio and television receivers as well as for laboratory work involving research and design.
With an Oscilloscope,the wave shape of a signal can be studied with respect to amplitude distirtion and deviation from the normal.Also we can measure voltage,frequency and phase shift by using an Oscilloscope.
The normal form of Cathode Ray Oscilloscope uses a horizontal input voltage which is an internally generated ramp voltage called "Time Base".This horizontal voltage moves the luminous spot periodically in a horizontal direction from left to right over the display area or screen.The vertical input to the CRO is the voltage under investigation.The vertical input voltage moves the luminous spot up and down in accordance with the instantaneous value of voltage.The luminous spot thus the traces the waveform of the input voltage with respect to time.When the input voltage repeats itself at a fast rate,the trace (Display) on the screen appears stationary on the screen.The Cathode Ray Oscilloscope thus provides a means of showing(Visualizing) time varying voltage.As such,the CRO has become a universal tool in all kinds of electric and electronics investigations.
Cathode Ray Oscilloscope operate on voltage.However,it is possible to convert current,strain,acceleration,pressure and other physical quantities into voltage with the help of transducers and thus to present visual representations of a wide variety of dynamic phenomena on CRO.
CRO are also used to investigate waveforms,transient phenomena,and other time varying quantities from a very low frequency range to the radio frequencies.
Oscilloscope have been evolved continuously,and they are now available which can measure frequencies upto 1 Giga hertz and observer events as small as 20 hertz. in duration.
Many additional features are available with some Oscilloscopes and these are includes built in Digital multimeters and Counters.
The Oscilloscopes are progressively getting smarter,and many are Microprocessor controlled.They have the ability to calculate several features such as rise time or pulse width of the measured waveform,and to display these values along with the display of the waveforms.They are easier to use and internal routines often act as a guide for the user,and display a warning if there is any error in setting.
Although,most Oscilloscope are monochromatics,colour Oscilloscope are finding increasing applications in computers and television.
The application of Oscilloscope have been enhanced on account of many recent developments.Most present days Oscilloscope are capable of accepting two or more inputs displaying them simultaneously.
This may be achieved through,using a split beam or by using a multiple beam tube.Sampling Oscilloscope are used for high speed applications.These Oscilloscope employ time sampling through and through their use it is possible to measure signals of about 20 Giga hertz.They can only detect a repetitive waveform and work on the principle of taking sample once every cycle,over several cycles,each sample point being shifted from the previous point.The complete picture of the waveform is stored and can displayed as a stationary signal.
Sunday, May 11, 2008
What are the different types of materials used for Semiconductors.
An electronics engineer comes in contact with a large variety material in the manufacturing of a apparatus,electronic machines & electronics devices,radio,TV,electronic gear,automatic & remote control equipment.In transmission line design,we must have knowledge material.In computer memory device too,
We must have an understanding of the construction of IC's & Semi Conducting materials.The materials used in various branches of electronics engineering they are divided into two large groups.
The first group comprises of construction materials which mainly go into the manufacture of bearing and auxiliary parts and components of electrical and radio devices,such as mounting frames,cases,dials,heat sinks,etc...
The second groups includes materials use for the fabrication Wires,Cabels,Wave guides,Antennas,Insulators,Capacitors,Resistors,Inductors,Transformers,Electric Motors & Generators,Magnets,Diodes & Transistor,FET& integrated Circuits (IC),Electromechanical Transducers,Lasers,Light Detectors,Computer memory devices & so on.
According to electrical properties,the materials can be classified into the following groups.
01)Conductor materials
02)Semiconductor materials
03)Super Conductor materials
04)Magnetic materials
05)Ferromagnetic materials
06)Insulating materials (Dielectrics)
07)Ferromagnetic materials
08)Ferroelectric materials
09)Gaseous Insulator
10)Gaseous Conductors
In this fast developing society,electronics is the most important branch of engineering.Electronics devices are being used in almost all the industries for the quality controls and automation.the branch of electronics which deals with current conduction through a vacuum or gas or semiconductor.
Now we will see about semiconductor.
Certain substances like Germanium,Silicon,Carbon etc.. are neither good conductor like copper nor insulators like glass,wool,rubber etc. that's why we can say,semiconductors are those substances whose electrical conductivity lies between conductors and insulators,for example Germanium,Silicon,selenium,carbon.The resistivity of semiconductor materials lies between 0.01 to 50 ohm centimeter at room temperature.The resistivity of semiconductor is not constant,but varies with many factors.The resistivity can be controlled by an electric field,voltage,temperature,illumination and impurity.Such resistivity controlled materials then works as transistors,varistors,photoelectrics and rectifiers.
Properties of Semiconductors.
01)The resistivity of semiconductor is less than an insulator but more than a conductor.
02)Semiconductors have negative temperatures coefficient of a resistance. i.e.The resistance of semiconductors decreases with the increasing temperatures and vice versa. for example Germanium actually an insulator at low temperature but it becomes a good conductor at high temperature.
03)When a suitable metallic impurity ( Arsenic,Gallium etc.) is added to a semiconductors,it's current conducting properties changes appreciably.This is the most important property.
We must have an understanding of the construction of IC's & Semi Conducting materials.The materials used in various branches of electronics engineering they are divided into two large groups.
The first group comprises of construction materials which mainly go into the manufacture of bearing and auxiliary parts and components of electrical and radio devices,such as mounting frames,cases,dials,heat sinks,etc...
The second groups includes materials use for the fabrication Wires,Cabels,Wave guides,Antennas,Insulators,Capacitors,Resistors,Inductors,Transformers,Electric Motors & Generators,Magnets,Diodes & Transistor,FET& integrated Circuits (IC),Electromechanical Transducers,Lasers,Light Detectors,Computer memory devices & so on.
According to electrical properties,the materials can be classified into the following groups.
01)Conductor materials
02)Semiconductor materials
03)Super Conductor materials
04)Magnetic materials
05)Ferromagnetic materials
06)Insulating materials (Dielectrics)
07)Ferromagnetic materials
08)Ferroelectric materials
09)Gaseous Insulator
10)Gaseous Conductors
In this fast developing society,electronics is the most important branch of engineering.Electronics devices are being used in almost all the industries for the quality controls and automation.the branch of electronics which deals with current conduction through a vacuum or gas or semiconductor.
Now we will see about semiconductor.
Certain substances like Germanium,Silicon,Carbon etc.. are neither good conductor like copper nor insulators like glass,wool,rubber etc. that's why we can say,semiconductors are those substances whose electrical conductivity lies between conductors and insulators,for example Germanium,Silicon,selenium,carbon.The resistivity of semiconductor materials lies between 0.01 to 50 ohm centimeter at room temperature.The resistivity of semiconductor is not constant,but varies with many factors.The resistivity can be controlled by an electric field,voltage,temperature,illumination and impurity.Such resistivity controlled materials then works as transistors,varistors,photoelectrics and rectifiers.
Properties of Semiconductors.
01)The resistivity of semiconductor is less than an insulator but more than a conductor.
02)Semiconductors have negative temperatures coefficient of a resistance. i.e.The resistance of semiconductors decreases with the increasing temperatures and vice versa. for example Germanium actually an insulator at low temperature but it becomes a good conductor at high temperature.
03)When a suitable metallic impurity ( Arsenic,Gallium etc.) is added to a semiconductors,it's current conducting properties changes appreciably.This is the most important property.
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