0
For most servicing applications, amperage is not a constant. For example, servicing a fan motor on an airconditioning unit: Voltage is never the exact same 250volts at every residence, a change in voltage will change the amperage. Other performance related factors are also involved. However, for such servicing, the amperage must fall below a prescribed maximum to prevent damage. As long as amperage draw is low enough, perfect precision is not needed. In more precise applications, such as micro-circuitry, all parts are designed to operate at specific voltages with exact resistances which creates a mathmatically predictable amperage draw. The proper voltages/amperages are maintained with specially designed regulators.
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 120V or 230V, it is the resistance that determines how much current shall be drawn from the source. If the resistance increases the current will drop (assuming constant voltage) I=V/R (Ohms Law) Since the ammeter is going to be used to measure the current that is being drawn from the source in an existing circuit you dont want to compromise the results of the measurement. Say an ammeter has an internal resistance of Ra=0.05 ohms and the resistance of the circuit is Rc=500 ohms, the nect reistance will be Rt= 0.05+500 = 500.05 ohms. This is a neglible increase in toral resistance of the circuit hence the current measured shall remain fairly accurate but consider the alternative if an ammeter has Ra = 50 ohms nor the total resistance of the circuit shall be Rt= Ra + Rc = 500 +50 =550 ohms. 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).
Add your answer:
Earn +20 pts
Why should you be the internal resistance of the very few Amitr?
ammeter connect in series in circuit to measure the current, if the Ammeter have a high resistance it would effect the voltage value because there will be a drop voltage over the internal resistance of the Ammeter, so we desgin the ammeters with very low resistance...
Why the resistance of an ammeter is bery low?
0. An ammeter is placed in series with the circuit in question; if its' internal resistance is high, it will change the current flow, thus making the measurement meaningless. For the same reason an ideal voltage meter will have infinite resistance.
Why does voltmeter have high internal resistance?
No, ammeters have a low internal resistance. This is so that when they are put in series with a circuit, they change the circuit's operating characteristics as little as possible.Contrast this with voltmeters, which do have a high internal resistance, and which are intended to be placed in parallel with the circuit they are measuring.Use the link below to the related question on why ammeters have a low internal resistance and read through that information to see why things are the way they are.
Is it desirable for a battery to have a high internal resistance?
No, it is desirable for a battery to have a low internal resistance.
Why in an ammeter low resistance is connected in parallel with the coil?
For protection.. Since the current prefer the short cut ..
Why should you be the internal resistance of the very few Amitr?
ammeter connect in series in circuit to measure the current, if the Ammeter have a high resistance it would effect the voltage value because there will be a drop voltage over the internal resistance of the Ammeter, so we desgin the ammeters with very low resistance...
Why the resistance of an ammeter is bery low?
0. An ammeter is placed in series with the circuit in question; if its' internal resistance is high, it will change the current flow, thus making the measurement meaningless. For the same reason an ideal voltage meter will have infinite resistance.
Why does voltmeter have high internal resistance?
No, ammeters have a low internal resistance. This is so that when they are put in series with a circuit, they change the circuit's operating characteristics as little as possible.Contrast this with voltmeters, which do have a high internal resistance, and which are intended to be placed in parallel with the circuit they are measuring.Use the link below to the related question on why ammeters have a low internal resistance and read through that information to see why things are the way they are.
The internal resistance of ammeter is?
The internal resistance of an ammeter is very low. This is necessary in order to minimize the impact of the ammeter on the circuit being measured, ensuring accurate readings of the current flowing through the circuit.
What will happen if ammeter is put across a resistance in a circuit?
Maybe blow the fuse or burn out the wiring. An ammeter has an extremely low resistance. connecting it across the resistance causes the resulting parallel resistance to be slightly lower than the resistance of the ammeter 1/Rt = 1/R + 1/R(ammeter)
1 What is the effect caused by the ammeter resistance when an ammeter is inserted into a circuit to measure the current?
An ammeter has a finite resistance which is inserted in series with the rest of the circuit, increasing the total resistance and decreasing the current. A good ammeter has a very low resistance, so it shouldn't affect the circuit noticeably.
Why are there more than two terminals on some ammeters and voltmeters?
A volt meter needs a high internal resistance not to influence the measurement, an ammeter needs a low internal resistance. Sometimes the easiest way to make that happen is to have different connectors.
Is the input resitance of an ideal ammeter is low and the output resistance is high?
An ammeter does not have an 'output resistance'. It's important that its resistance is low so as not to add additional resistance into the circuit to which it is connected, otherwise the 'measured current' would be lower than the actual current.
Do meters usually have a high or low internal resistance?
It depends on the application. Voltmeters have a high internal resistance, while ammeters have a low internal resistance.
What happens when an ammeter is connected in parallel with a circuit?
SMOKE!!! Yiii-haaaa! An ammeter is always as low a resistance as possible. That way, the current that you measure in a circuit using the meter will be the same as if the meter were not there. So putting an ammeter in parallel with a circuit means that you just short circuited the circuit you were intending to measure. Poof! There goes your ammeter!An ammeter has a very low internal resistance. So, if it is connected in parallel with a load, it will short-out that load. The resulting high current flowing through the ammeter may severely damage the meter (and possible harm the user), although most are fitted with fuses to protect them.
Compare how an ammeter and voltmeter are connected in a circuithow are they different?
ammeter connected sereal. internal resestance very low volt meter connected parrel. high internal resestance.
Why should a millimeter have a low resistance?
A millimeter should have low resistance to allow for easy flow of fluid or air through the tube. High resistance would inhibit the movement of substances and make it difficult for them to travel efficiently across the millimeter, affecting its functionality. A low resistant millimeter ensures optimal performance and accuracy in various applications.
