The significant portion of the measurand current passes to the shunt because of the low resistance path and few amount of current passes through the ammeter. The shunt connects in parallel to the ammeter because of which the voltage drops across the meter and shunt remain the same. Thus, the movement of the pointer is not affected by the shunt. Consider the circuit used for measuring the current I. The circuit has ammeter and shunt which is connected parallel to each other.
The ammeter designs for measuring the small current say, I m. The magnitude of the current I passes through the meter is very high, and it will burn the meter. For measuring the current I the shunt is required in the circuit. 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.
An ammeter measures current in a circuit and high internal resistance would change the circuits current flow. An ammeter must have very low near zero series resistance. A voltmeter, in comparison, must have very high internal resistance.
Alfred c. Use an ohmmeter such as a D. 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.
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. Pull up a chair. An ammeter with an internal resistance of 0. 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. Focus again. Let's recap. The meter, with an internal resistance of 0. Let's check our work. A max of 1 amp through the meter, whose resistance is 0.
We have the both those bits of data. Let's do the math. 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.
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 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.
An ammeter measures current. When you connect an ammeter always in series to the circuit you want to measure the current passing through the circuit. Resistance acts as the driving force in a circuit. Generally the supply is fixed at say V or V, it is the resistance that determines how much current shall be drawn from the source. Now the measurement is influenced by the ammeter resistance. To avoid the error in result an ammeter must have very low ideally zero resistance whereas a voltmeter must have very high resistance ideally infinity.
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 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.. Since the voltage across the ammeter is equivalent to the resistance of the ammeter times the current through the meter, it is necessary to minimize the ammeter's resistance.
This potential difference can be calculated using Ohm's Law. Previous Next. Electronics Basics What is a Transistor? What is a Diode? What are SiC Power Devices? What are SiC Semiconductors? What is IGBT? What are LEDs? What is a Photointerrupter? What is a laser diode? What is a Resistor? What is Tantalum Capacitor? What is Binary? What are Opamps? What are Opamps and Comparators? What is Semiconductor Memory?
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