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Why should you be the internal resistance of the very few Amitr?
Wiki User
∙ 14y ago
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...
Wiki User
∙ 14y ago
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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.
What is meant by the internal resistance of a battery?
There is internal resistance in a battery because a battery is not an ideal voltage source. It may be close, but it is not ideal. As a result, analytically, there will be some series resistance, resistance which places a limit on the maximum current that the battery can provide. While no battery is ideal, most are sufficiently ideal to not require any consideration of the internal resistance. If your circuit is dependent on the internal resistance of a battery, then it is probably not well suited for that application.
Why emf does not depend on resistance?
Because emf is the very source of voltage, either chemical or inductive, an can be meassured at open circuit only so, internal resistance of the supplier is not affecting it.
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.
Is the emf of a cell equal to the total potential drop in the external circuit of the cell?
The EMF of a cell is the voltage across the terminals at zero current. This is the quoted cell voltage but as soon as a current is dawn from the cell, the voltage will drop. It's due to the internal resistance of the cell. In a circuit diagram, a cell is often shown as a voltage source (a perfect source) and a resistor in series to represent the internal resistance. Using Ohms Law, it can be seen that as soon as a current flows, a voltage will be developed across the internal resistance, so reducing the voltage that is seen at the terminals of the cell. The higher the current draw, the higher the voltage drop inside the cell. Normally, the voltage drop is minimal but in most cells, as it loses charge, the internal resistance rises. Eventually it will reach the point where most of the voltage is dropped across the internal resistance, leaving little to drive the intended load. Often, if a battery is removed from a device and measured, the voltage will be measured as equal to or very close to the quoted cell voltage. It is easy to make a judgment that a battery is good when it is almost dead. The only way to confirm the state of the battery is to measure the voltage at the terminals while the load is attached. The results can be very different to the off load voltage. Alkaline cells have a low internal resistance compared to other dry cells. This makes them well suited for high current drain applications. The internal resistance also rises more slowly than most other cells, so they remain useful far longer than zinc-carbon types.
Do Dead batteries have high internal resistance?
yes, batteries have high internal resistance. The higher the resistance the lower power you get out of the batter. Therefore if you no power you have very high 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.
What is an reactance?
it is a internal resistance of the devices like as capacitor and inductorCommentAs 'resistance' has a very specific meaning, I suggest that the above answer should read: 'It is the opposition of devices like capacitors and inductors (to the flow of current).'
What is meant by the internal resistance of a battery?
There is internal resistance in a battery because a battery is not an ideal voltage source. It may be close, but it is not ideal. As a result, analytically, there will be some series resistance, resistance which places a limit on the maximum current that the battery can provide. While no battery is ideal, most are sufficiently ideal to not require any consideration of the internal resistance. If your circuit is dependent on the internal resistance of a battery, then it is probably not well suited for that application.
Why emf does not depend on resistance?
Because emf is the very source of voltage, either chemical or inductive, an can be meassured at open circuit only so, internal resistance of the supplier is not affecting it.
Why do you get different results when calculating the voltage drop across a resistor and ignoring resistance of a voltmeter and when considering it?
Voltage drop is the product of current and resistance. When you connect a voltmeter across a resistor, you are connecting that voltmeter's internal resistance in parallel with that resistor. The resulting resistance of this parallel combination is lowerthan that of the resistor. As a result the voltage drop (current times this lower resistance) will be lower than it would be without the voltmeter connected. This is called the 'loading effect' of that voltmeter.The higher the internal resistance of the voltmeter, the less effect it will have on lowering the overall resistance when connected across a resistor. This is why the internal resistance of a voltmeter is made deliberately very high. Under most circumstances, therefore, a conventional voltmeter will have very little effect on the resistance of the circuit being tested and, so, it will have no significant effect on the voltage appearing across the resistor.However... for circuits that already have exceptionally-high resistance values, you must be careful when you select a voltmeter as you must take into account its internal resistance and ensure the voltmeter you use has the very highest internal resistance available. This is because the loading effect increases with circuits that have a high resistance. That might involve selecting a voltmeter that works on a completely-different principle , such as an electrostatic voltmeter or, perhaps, an oscilloscope
Why short circuit and open circuit are equivalent appropriate?
In circuit equivalence, voltage and current sources are respectively equated to short and open ckt because of the very nature of them. A voltage source has zero internal resistance and current source has infinite internal resistance hence their equivalents:-)
Why the input impedence of op-Amp is very high?
An ideal amplifier will have a very high input resistance, and low output resistance. This is so it doesn't "load" the input circuitry, and can drive output circuitry. Say you hooked an op amp up to a microphone that kicked out 100mV unloaded. If you shorted out the microphone, the output would approach 0mV (very low resistance load). If you connected a very high resistance load instead, the output would remain close to 100mV. As the load becomes a smaller resistance/bigger load, the output voltage will decrease until it is no longer useful. This is because the microphone has an internal resistance that remains constant while you're varying the attached load. The voltage drop across the internal resistance will increase as current output increases, causing less of a signal to be delivered to the amplifier.
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.
What should you do if you have internal bleeding?
well internal bleeding is very serious. if you think you have some then you must call a doctor as it is a matter of life or death
What should a bad motor read in ohms if it is bad?
If an Alternating Current (a/c) motor is bad. The resistance will read very hi as in an open winding. ie: meg ohms Or very low as in a shorted winding. ie: 0.01 ohms It must not read any resistance to the housing or shaft. The resistance between leads should be a reasonable value and can be determined with : electromotive force divided by inductance equals resistance. example: 215 volt alternating current with name plate full load amperes of 10 should read very near 21.5 ohms resistance between leads.
What offers resistance to the circuit and limits the amount of current that can flow?
The internal components of a device that has been manufactured by a company adds up to the internal resistance of the device. Some devices are higher in resistance, some are lower. The results that you can see is on the device's nameplate and is represented by the wattage that the device draws.To answer the second part of the question, the answer is Ohm's law. The current of a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. In other words if the voltage remains the same, the higher the resistance the lower the current draw. A short circuit is no resistance, very high current. This is why over current protection is needed in most electrical circuits.
