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An ammeter has to measure to current flowing through the circuit. Resistance offers an obstruction to the current flow. So, if the resistance of an ammeter is large , the current measured by the ammeter will be quite less as compared to the actual amount of current flowing through the circuit which is undesirable. If ammeter has zero resistance , then it will give the exact value of current. But this is not practically possible because every material has some value of internal resistance which we can't control. For this reason , ammeter must have small resistance
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Why shunt resistance used in ammeter and why is it connected in parallel?
An ammeter's coil requires very little current for full-scale deflection (fsd). So, to measure a current above its fsd value, most of that current must be allowed to bypass the coil. This is achieved by placing a very low value shunt resistance in parallel with the coil ('shunt' is an archaic word for 'parallel').
What is the effect caused by ammeter resistance when an ammeter is inserted into a circuit to measure the current?
The effect the multimeter might have on the circuit when inserted to measure the current is to increase the circuit resistance and decrease the available voltage to the circuit. This is because the multimeter in amps or milliamps mode does have a small resistance which is not zero, so by Ohm's law, there is a voltage drop across the multimeter; small, but not zero. Usually this effect is small. One way to compensate is to start by measuring voltage, and then inserting a separate ammeter and adjusting the power supply to match the original voltage. Of course, the voltmeter must be downstream of the ammeter.
Why does an ammeter have a low resistance while a voltmeter has high resistance?
I am going to assume that you mean low "resistance" in an open circuit test and are performing this with a multimeter. An ammeter works by place a very small amount of resistance in series with a circuit and then measuring the Voltage drop across the resistance. The Voltage is directly proportional to the current as given in ohms law: E = I x R If you are measuring the resistance through the ammeter it will have a very low resistance and impedance.
What would happen if a voltmeter were substituted for an ammeter?
Smoke. Since a voltmeter is in parallel with the load it is right across the source voltage. Putting the amp meter across the line with its low resistance it will act like a fuse, hence the smoke. Newer solid state testers are usually smarter that the operators. They have built in circuitry which sense the wrong settings you are using and shut the tester off with a "beep" to let you know that you are doing something wrong.
What is the difference between ammeters and amp meters?
An Ammeter connects a low impedance on the test points, so the equivalent of that is a "short circuit" between the test points. This is done to avoid a drop of current on the tested circuit. A Voltmeter connects a high impedance on the test points, so the equivalent of that is a "open circuit" between the test points. This is done to avoid a drop of voltage on the tested circuit. --------- In terms of external connections Ammeter (used to measure current) is connected in series of the circuit (through which the current flow need to be measured) and voltmeter (used to measure voltage) is connected in parallel to points in circuit (across which voltage needs to be measured).
Why shunt resistance used in ammeter and why is it connected in parallel?
An ammeter's coil requires very little current for full-scale deflection (fsd). So, to measure a current above its fsd value, most of that current must be allowed to bypass the coil. This is achieved by placing a very low value shunt resistance in parallel with the coil ('shunt' is an archaic word for 'parallel').
What must an ammeter be connected to?
To a very small resistance so a mv can be measured as a function of amperes.
Why must you make current flow through the meter in order to measure it?
You don't. ...unless you want to directly measure the current in a circuit branch. That's the purpose of an ammeter. You can also use a volt meter if you know the resistance of a resistor in that branch to determine current (assuming DC circuit here) - current = voltage / resistance. This may be more useful for circuitry that is on a breadboard, since inserting an ammeter may not be practical.
Why ammeter is not used as a low resistance meter?
the function of an ammeter "is to measure the rate of current flow from the alternator to the battery".-Small Gas Engines, Ninth edition. Alfred c. Roth. Use an ohmmeter such as a D.V.O.M. to measure resistance. (Everything has a specific task in a vehicle. If there is no current through the ammeter, then one must trouble shoot the entire ignition system.
Why should a millimeter have a low resistance?
An ammeter is placed in series with a circuit in order to measure the current. If it has any appreciable resistance, inserting the ammeter will increase the normal resistance of the circuit and reduce the value of the current flowing through it. The ammeter will, therefore, give an inaccurate reading (under-read). So the ammeter must have a very low resistance so that it has the minimum effect on the normal resistance of the circuit being tested. Ideally, the ammeter should have zero resistance but, of course, this is impossible.
What is the effect caused by ammeter resistance when an ammeter is inserted into a circuit to measure the current?
The effect the multimeter might have on the circuit when inserted to measure the current is to increase the circuit resistance and decrease the available voltage to the circuit. This is because the multimeter in amps or milliamps mode does have a small resistance which is not zero, so by Ohm's law, there is a voltage drop across the multimeter; small, but not zero. Usually this effect is small. One way to compensate is to start by measuring voltage, and then inserting a separate ammeter and adjusting the power supply to match the original voltage. Of course, the voltmeter must be downstream of the ammeter.
Do you can connect a multiplier resistance is series despite a shunt resistance in parallel in ammeter . and why?
An ammeter is connected in series in a branch of the circuit carrying current, and measures the current in that branch. The resistance of the meter must be very low ... ideally zero ... in order to avoid influencing the circuit when it's installed. If you intentionally insert a resistance in series with the meter, then inserting the meter in a circuit changes the current in that branch. In general, it's not acceptable for the act of measuring to change the quantity being measured, unless you are closely related to Werner Heisenberg..
Why does an ammeter have a low resistance while a voltmeter has high resistance?
I am going to assume that you mean low "resistance" in an open circuit test and are performing this with a multimeter. An ammeter works by place a very small amount of resistance in series with a circuit and then measuring the Voltage drop across the resistance. The Voltage is directly proportional to the current as given in ohms law: E = I x R If you are measuring the resistance through the ammeter it will have a very low resistance and impedance.
Why motor has large winding in shunt resistance than armature resistance?
A motor with large windings will have greater shunt resistance than armature resistance due to the sheer amount of copper wire it must travel through. The gauge of the wire also plays a part in this process.
If an ammeter reads up to 1 ampere and its internal resistence is 0.81 ohms what value of shunt resistance is required to increase the range to 10 A?
Pull up a chair. An ammeter with an internal resistance of 0.81 ohms has a max current of 1 amp. We want to increase its range to 10 amps with a shunt resistance. Now focus on this. The shunt will be connected in parallel with the meter. (It's a shunt resistor, so that's what that means.) The max the meter can carry is 1 amp, so the shunt, which is in parallel with the meter, will have to carry 9 amps around the meter. That means the 1 amp through the meter will be added to the 9 amps of shunt current through the shunt resistor to give us the 10 amps of total current that was asked to be measured. Make sense? Review time. The meter carries 1 amp (it's max current) and the shunt carries 9 amps around the meter. That means the shunt has less resistance than the meter so it can carry all that extra current around the meter. How much less is the resistance? That's what will lead us to the answer to the question. We have 0.81 ohms in parallel with some smaller resistance, Rs, the value of the shunt resistor. Focus again. The shunt must carry 9 times as much current as the meter, so the shunt resistor's value must be 1/9th as much as the meter's. Make sense? Let's recap. The meter, with an internal resistance of 0.81 ohms is going to be 9 times as resistive as the resistance of the shunt. The meter will carry 1/9th as much current as the shunt, so the shunt, which carries 9 times the current of the resistor, will be able to carry that much more current because it's only 1/9th as resistive. The shunt resistance, Rs, is 1/9th the value of the internal resistance of the meter, RIm, and that makes the math easy. Rs = RIm / 9 = 0.81 ohms / 9 = 0.09 ohms The shunt will have to have a resistance value of 0.09 ohms. Let's check our work. A max of 1 amp through the meter, whose resistance is 0.81 ohms works out to 0.81 volts dropped across that meter. Em = Im x Rm = 1 amp x 0.81 ohms = 0.81 volts (voltage dropped across the meter) Our shunt will have the same identical voltage drop (it must have!) and 9 amps of current through it, right? Yes. We have the both those bits of data. Let's do the math. Rs = Es / Is = 0.81 volts / 9 amps = 0.09 ohms (the shunt's resistance is 0.90 ohms) Our work checks. And if you were wondering if the second approach could have been used as the primary means of solving the problem, the answer is, "Yes, it can." Either method will solve the problem, and the answer can be checked with the other approach.
If An ammeter shunt has a voltage drop of 50 mega volts when 50 Amps of current flows through it what is the resistance of the shunt?
R = E / I= (50 x 106) / (50)= 1 megohm.Strange for a "shunt". Must be across one heck of a meter movement !It looks like the question was misworded. Instead of 50 megavolts, perhaps it should have been 50 millivolts. In that case the meter/shunt impedance would have been 0.001 ohms. In any case, the actual value of the shunt resistor would depend on the impedance of the meter itself. In the latter (assumed) case, this is probably negligible, so the shunt does appear to be 0.001 ohms.
What would happen if a voltmeter were substituted for an ammeter?
Smoke. Since a voltmeter is in parallel with the load it is right across the source voltage. Putting the amp meter across the line with its low resistance it will act like a fuse, hence the smoke. Newer solid state testers are usually smarter that the operators. They have built in circuitry which sense the wrong settings you are using and shut the tester off with a "beep" to let you know that you are doing something wrong.
