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Why in an ammeter low resistance is connected in parallel with the coil?
Wiki User
∙ 6y ago
For protection.. Since the current prefer the short cut ..
Wiki User
∙ 9y ago
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Why wouldn't the shunt resistor in the ammeter protect the ammeter when the ammeter is connected in parallel?
Connecting an ammeter in parallel subjects that ammeter to the full supply voltage. The shunt resistor is not designed to sustain that value of voltage and will burn out. Also, the clue is in the word 'shunt' (which means 'in parallel') which means that the coil will also burn out!
What happens when an ammeter is connected wrong?
Ammeters have a low impedance, so if they are incorrectly connected in parallel to your load instead of in series, more current will flow through the circuit and the ammeter will almost act like a short. There is potential to burn our the ammeter.
How do you connect more than one ammeter to a circuit?
Two ways to connect an ammeter, You can use a direct reading type, by connecting the ammeter in series with the load. You can use a current transformer type or CT. The current transformer looks like a wire wrapped donut with two terminals on its side with a hole through the middle. you pass the wire carrying the load through the center. Connect the direct reading meter to the two terminals. A CT type meter allows you to measure higher currents.
What is the purpose of the series resistor in your designed ammeter circuit?
You appear to be referring to a 'swamping resistor' which is connected in series with a moving-coil ammeter's moving coil.To minimise any errors due to temperature changes in the resistance of the instrument's moving coil, the coil is connected in series with what is termed a 'swamping resistor' whose resistance is large in comparison with that of the moving coil, and which is manufactured from an alloy with a very lowtemperature coefficient of resistance (i.e. a metal whose resistance is hardly effected by wide variations in temperature).For example, if the resistance of a 1-Ω moving coil increases to, say, 1.1 Ω, when its rated current flows through it, this will introduce a 10% error in the instrument's reading.But by calibrating the instrument with a series swamp resistor of, say, 49 Ω, the overall resistance at rated current will become 50.1 Ω. This will result in an error of just 0.2%.A swamping resistor, then, is an integral part of all moving-coil instruments and, when we refer to an instrument's 'coil resistance', we actually mean the combined resistance of the moving coil itself and its swamping resistor.
What is function of pressure coil in a watt meter?
A 'pressure coil' is an archaic term for a 'voltage coil' (UK terminology) or 'potential coil' (US terminology), as opposed to the 'current coil' in a wattmeter. This coil is connected in parallel with the supply, while the current coil is connected in series with the load.
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').
Which of the coil of the wattmeter has high resistance?
The voltage (or 'potential') coil has the higher resistance, because it is connected in parallel with the load.
Why wouldn't the shunt resistor in the ammeter protect the ammeter when the ammeter is connected in parallel?
Connecting an ammeter in parallel subjects that ammeter to the full supply voltage. The shunt resistor is not designed to sustain that value of voltage and will burn out. Also, the clue is in the word 'shunt' (which means 'in parallel') which means that the coil will also burn out!
Working principle of ammeter?
An ammeter consists of a coil with very low resistance. when electric current flows through the coil, the coil induces a magnetic field which turns the needle.
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.
How wattmeter is connected in circuit?
A wattmeter has two coils: a current coil and a voltage coil. The current coil is connected in series with the load, while the voltage coil is connected in parallel with the load (just in the same way an ammeter and a voltmeter are connected). The wattmeter's polarity markings must be observed while making these connections -if the wattmeter reads 'downscale' (backwards), then the connection to either one (but not both) of the coils must be reversed.
What happens when an ammeter is connected wrong?
Ammeters have a low impedance, so if they are incorrectly connected in parallel to your load instead of in series, more current will flow through the circuit and the ammeter will almost act like a short. There is potential to burn our the ammeter.
How do you connect more than one ammeter to a circuit?
Two ways to connect an ammeter, You can use a direct reading type, by connecting the ammeter in series with the load. You can use a current transformer type or CT. The current transformer looks like a wire wrapped donut with two terminals on its side with a hole through the middle. you pass the wire carrying the load through the center. Connect the direct reading meter to the two terminals. A CT type meter allows you to measure higher currents.
How is a shunt coil installed?
'Shunt' is an archaic term, meaning 'in parallel with'. So a 'shunt coil' is connected 'in parallel' with... With what, of course, depends upon what sort of device you are talking about. For example the field coil of a d.c. shunt-connected motor has its field winding connected in parallel ('shunt') with the supply.
What is the purpose of the series resistor in your designed ammeter circuit?
You appear to be referring to a 'swamping resistor' which is connected in series with a moving-coil ammeter's moving coil.To minimise any errors due to temperature changes in the resistance of the instrument's moving coil, the coil is connected in series with what is termed a 'swamping resistor' whose resistance is large in comparison with that of the moving coil, and which is manufactured from an alloy with a very lowtemperature coefficient of resistance (i.e. a metal whose resistance is hardly effected by wide variations in temperature).For example, if the resistance of a 1-Ω moving coil increases to, say, 1.1 Ω, when its rated current flows through it, this will introduce a 10% error in the instrument's reading.But by calibrating the instrument with a series swamp resistor of, say, 49 Ω, the overall resistance at rated current will become 50.1 Ω. This will result in an error of just 0.2%.A swamping resistor, then, is an integral part of all moving-coil instruments and, when we refer to an instrument's 'coil resistance', we actually mean the combined resistance of the moving coil itself and its swamping resistor.
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).
How can you measure the ampere or watt for power supply?
You can measure the current and power of a 'power supply', using an ammeter and a wattmeter. With the power supply connected to its load, the ammeter must be connected in series with the power supply's input. The wattmeter's current coil must also be connected in series with the power supply's input, and its voltage coil must be connected in parallel with the supply, taking the instrument's polarity markings into account.
