In other words, calibration checks the correctness of the instrument by comparing it. This is a null method, in which no meter reading needs be taken except for a judgment of when the deflection of a galvanometer has been reduced to zero. As mentioned above, we will use a suitable stable dc supply voltage to avoid the errors in calibration which do not produce voltage fluctuations during the entire experiment. Let the range of the ammeter be 0 i0 amp and we convert it to a voltmeter of range 0 v0 volt. No name of the experiment 1 calibration and testing of single phase energy. Now the ammeter which converted to a voltmeter should have the full scale read out when 5 volt is connect to it. Accuracy of the basic meter or calibrate and display on the scale of the meter, for functional applications, like displaying a parameter with engineering units like rpm, kgcm2 or 0c etc. This circuit avoids most of the difficulties of the ammetervoltmeter method. This experiment will guide students through making a labmade voltmeter and ammeter using a galvanometer and resistors. Potentiometer calibration of pmmc ammeter and pmmc voltmeter 4. Demonstration of various instruments like ammeter, voltmeter.
A voltmeter is connected in parallel with a device to. The following experiments are required to be conducted as compulsory experiments. Conversion of ammeter to voltmeter converting an ammeter to a voltmeter involves increasing the resistance of the ammeter. Voltmeter connected to battery and reading obtained resistance box added and circuit is adjusted so that voltage reading is 12 of former value current in second case is half current in first case total voltage is the same voltmeter resistance is the same as added resistance. Watch this video to know more about calibration of voltmeter. Measurement of voltage, current, and resistance using the multimeters provided in the lab. This measured resistance rm will be the true value of the resistance if and only if the resistance of ammeter is zero and that of voltmeter is infinite.
The experiment is repeated by varying the curden and setting different values for iss. So in such cases three voltmeters or three ammeter method is used continue reading three voltmeter method. The accuracy of an analog ammeter or voltmeter is usually stated as a. An ammeter is a low impedance device that measures the current going through a circuit, often by measuring the small voltage across a known resistance. Measurement of 3 phase power with single watt meter and 2 nos of c. Taking the same meter movement as the voltmeter example, we can see that it would make a very limited instrument by itself, fullscale deflection occurring at. To calibrate voltmeter and ammeter using potentiometer answers. The resistance of voltmeter is kept very high by connecting a high resistance in series of the voltmeter with the current coil of the instrument. We are required to calibrate the voltmeter to ideal readings. For the conversion of galvanometer to ammeter ga a low resistance shunt resistance s is. Inbuilt voltmeter, ammeter, wattmeter as standard meter for. Imprecise ohmmeter made from galvanometer, series resistor, variable resistor, and a dc voltage source.
The calibration is the process of checking the accuracy of the result by comparing it with the standard value. An ammeter is a measuring device used to measure the electric current in a circuit. Calibration of ammeter and voltmeter using potentiometer. To study and perform calibration of ac voltmeter and ac ammeter objective. If the voltmeter reading is v and ammeter reading is i then the measured resistance will be. Verification of ohms law using ammeter and voltmeter. Pandey conversion of galvanometer to ammeter object.
You need a calibrated and certified ammeter, certified by a standard or recognized calibration laboratory, which covers the required current range. Calibration of the converted ammeter converted ammeter standard ammeter correction. A galvanometer is an instrument used to detect and measure small electrical currents. For an ammeter you should measure its internal resistance or impedance if it is ac ammeter. The complete set up consists of two energy meters, wattmeter, voltmeter. Understanding the structure of the ammeter, voltmeter, and ohmmeter. Ammeter ammeter is employed for measuring of current in a circuit and connected in series in the circuit. Ammeter design dc metering circuits electronics textbook. Calibrating ac voltmeters and ammeters for different fullscale ranges of operation is much the same as with dc instruments. When a current flows through it then torque acts on it. Calibration of ammeter and voltmeter electrical engineering. Why is it necessary to calibrate an ammeter and a voltmeter.
Potentiometer calibration of ammeter kisembo academy. Mar 23, 2018 you need a calibrated and certified ammeter, certified by a standard or recognized calibration laboratory, which covers the required current range. Calibration of voltmeter using dc potentiometer calibration of ammeter using dc potentiometer apparatus required. It is a complete setup with training board, potentiometer and calibration unit. Electrical measurements lab manual pdf em lab manual pdf. How you can do calibration of voltmeter by potentiometer. A meter designed to measure electrical current is popularly called an ammeter because the unit of measurement is amps. Viva voce on galvanometer to ammeter or voltmeter q. In this video i explain the calibration of a voltmeter using a potentiometer. Calibration of ammeter and voltmeter free download as word doc. Calibration of voltmeters and ammeter by potentiometer 2. To calibrate an ammeter, you need a 1 ohm reference shunt resistor or accurately measured shunt of low resistance in series with the meter and measure the voltage drop across the shunt with a potentiometer and calculate the current. We are required to calibrate the ammeter to know about its. Multimeter measurements on dc resistive circuits objectives.
In ammeter designs, external resistors added to extend the usable range of the movement are connected in parallel with the movement rather than in series as is the case for voltmeters. In other words, calibration checks the correctness of. Note that you need to have precise equipment for this, as currents flowing through a voltmeter are microampers, and voltage drops on ammeters are at most milivolts in typical solutions. The best method of calibration is to measure the true value of current or voltage in the circuit and compare it with the value measured by the given ammeter or voltmeter. The potentiometer is used extensively for the calibration of voltmeters and ammeters, and provides a standard method for calibration of these instruments. Nvis 6032 calibration of voltmeter and ammeter by potentiometer is an elite setup designed to understand the functioning and calibration of potentiometer, voltmeter and ammeter. As we know, wattmeters are used for measurement of power in inductance ac circuits, but in some cases it is not possible to use wattmeters because of their incorrect readings or sometime wattmaters may not available. To calibrate the given ammeter by using potentiometer. Calibration of single phase energy meter using phantom loading method with rss meter as standard 2. Conversion of galvanometer to ammeter home page of.
Learning how to use those meters and using them to measure the current, voltage, and resistance of an electric circuit. In this practical we will show you how to calibrate the voltmeter using a potentiometer. Experiment 4 voltmeter and ammeter tuesday, september 15 th, 2015 phy2049l dr. In both the cases, the reading of voltmeter and ammeter is taken. This approach assumes the ammeter has zero internal resistance.
Potentiometer calibration of voltmeter kisembo academy. Calibration of voltmeter and ammeter by potentiometer is an elite setup designed to understand the functioning and calibration of potentiometer, voltmeter and ammeter. Practical of calibration of voltmeter using potentiometer. Apr 05, 2018 a potentiometer can be used to calibrate a voltmeter by using a potentiometer to obtain a calibration curve for the voltmeter. For the most accurate measurement of resistance, the wheatstone bridge circuit is used. Potentiometer calibration of ammeter kisembo academy youtube. Measure the source current using the keithley 2000 and enter the current value on the data sheet. The true value of current or voltage in the circuit can be measured up to a fair grade of accuracy by using a potentiometer. To calibrate and testing of single phase induction type energy meter. Conversion of voltmeter to ammeter and viceversa objective. The experiment is repeated for different values of load current at constant. Mar 22, 20 verification of ohms law using ammeter and voltmeter posted on march 22, 20 by shah jamal ohms law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.
Get the signature on experiment result sheet daily. Ii electronic voltmeters and ammeters alessandro ferrero, halit eren encyclopedia of life support systems eolss when a voltmeter is configured, different fullscale values can be obtained by using selectableratio voltage dividers if the input voltage is higher than the amplifier dynamic range. The range of this meter is v imrm r where the multiplier resistance, r can be r 1 or r 2 or. Sigmas calibration lab presents electrical calibration which offers voltmeter calibration and multimeter calibration. Calibration of ammeter and voltmeter using potentiometer dr. Turn on the power supply and adjust it so that the output is 12v as measured on the fluke 45.
Voltmeters and ammeters are used to measure voltage and current, respectively. Demonstration of various instruments like ammeter, voltmeter, wattmeter, energy meter, tachometer, rheostat, various capacitors, various resistors, ac and dc power supply. Jan 08, 2019 in both the cases, the reading of voltmeter and ammeter is taken. Laboratory manual basic electrical engineering laboratory. This is done by adding a high resistance in series with the ammeter. Repeat the entire experiment, but this time with a slight variation to the circuit as shown in figure 3b. To calibrate voltmeter and ammeter using potentiometer. Calibration of voltmeter and ammeter using potentiometer. Multirange voltmeter a multirange voltmeter consists of a deflection instrument, several multiplier resistors and a rotary switch. Remove the voltmeter from the power supply and measure voltages across each of the resistors in the circuit. Instrumentation and oscilloscope introduction part 1.
The following sections describe a number of common requirements for calibration of electrostatic measuring instruments. Measurement of parameters of a choke coil using 3 voltmeter and 3 ammeter methods. Experiment 4 experiment 4 voltmeter and ammeter tuesday. Lendi institute of engineering and technology approved by a. Use a stable voltage source, preferably a variable voltage source or potentiometer to vary the c. A rheostat is used for adjusting the magnitude of the current flowing through the entire circuit. Calibration of dynamometer wattmeter using phantom loadingupf.
Learning how to use those meters and using them to measure the current, voltage, and. An ammeter is a device used to measure the current, that is the the. In other words, calibration checks the correctness of the instrument by comparing it with the reference standard. To learn how to determine uncertainty of meter readings. Multimeter, ammeter and breadboards in this lab we will become familiar with three instruments that you will use throughout the semester.
The instrument is based on the idea that when current flows through a wire, a magnetic field is produced. In this practical we will show you how to calibrate the ammeter using a potentiometer. Verification of ohms law using ammeter and voltmeter posted on march 22, 20 by shah jamal ohms law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. This circuit avoids most of the difficulties of the ammeter voltmeter method. Calibration unit has a voltmeter and an ammeter, which can be calibrated by potentiometer. Polar formcartesian form calibration of ac voltmeter, parameters of choke. Apr 05, 2018 potentiometer, as the name says, measures potential. Converting an ammeter to a voltmeter involves increasing the resistance of the ammeter. It is a device which measures the presence of current in circuit. To calibrate voltmeter with potentiometer physics practical. A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Calibration of volt and ameter using potentiometer.
How to calibrate a voltmeter using a potentiometer kisembo academy. Calibration of ammeter, voltmeter, and wattmeter using potentiometer. Range extension of ammeters voltmeters your electrical. Agilan bv physics practical in tamil potentiometer calibration of low. Not only ammeter or voltmeter, any measuring instrument needs to be precisely calibrated first before using it for any kind of measurement.
Then as seen from figure, the voltage drop across r is v. To convert weston galvanometer to a ammeter of current range 0 to a amp. We are required to calibrate the ammeter to know about its errors and adjust it to get near to ideal readings. It is because the division of current between the operating coil and the shunt varies with frequency since reactance of the coil depends upon. Calibration of pmmc voltmeter and ammeter by dc cromptons potentiometer po1,po2, pso2,pso3. You should have a total of two sets raw data tables by the end of this part. The actual voltage drop across the current coil of the voltmeter is only a fraction of the total voltage applied across the voltmeter which is to be measured. Potentiometer, as the name says, measures potential.
Introduction to various supply systems, ammeter, voltmeter, wattmeter, energy meter, tachometer, rheostat, loading devices, transformer. Oct 29, 2010 to calibrate voltmeter and ammeter using potentiometer set up of the apparatus is arranged in circuit. Measurement of power by 3voltmeter and 3ammeter methods. Every measuring instrument basically measures quantity you want to measure and displays a reading which. The instrument that used to be called a potentimeter was a rheostat and a galvanometer movement, a voltage reference and a momentary contact. Shunts can not be used to extend the range of movingiron ac ammeters accurately.
Calibration of dc ammeter and dc voltmeter students room. Measurement of power by using 3 voltmeter and 3 ammeter methods. Calibration of ammeter, voltmeter, and wattmeter using. The facility to connect external wattmeter or voltmeter and ammeter is also provided. Experiment 3 ammeters and voltmeters flashcards quizlet. Conversion of voltmeter to ammeter and viceversa niser.