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Why must you make current flow through the meter in order to measure it?
Wiki User
∙ 12y ago
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.
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoYou must make current flow through anything in order for the effect of the current to be "noticed". Without current flow, you can have no work, and you can have no effect. In the case of the ammeter, there is a large shunt resistance across the meter. most of the current shunts through that resistance, but a very small part goes through the meter, which registers the current flow and indicates a proportional flow that is calibrated to the ratio of the meter's resistance versus the shunt resistance.
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Why use AC to measure ionic conductance and why not dc current?
in order to avoid electrolysis
What does electromagnetism have to do with galvanometer?
A galvanometer is a simple meter that detects the flow of current. A current flowing in a wire causes magnetism around the wire. This is called electromagnetism. Like poles of a magnet repel and opposites attract. The Galvanometer uses these principles in order to move a pointer across a scale.
What happens when voltmeter is connected in parallel?
An ideal voltmeter has infinite impedance(resistance). If you were to break the circuit and put it in series and try to make a measurement, it is easy to see that the circuit would act completely differently and your measurement would be wrong. An ideal ammeter is always connected in series because it has 0 resistance, so all of the current would flow through it, and not through the wire that you are trying to measure the current of.A better answer though is to think about what you are trying to measure. When you say something is 3 Volts, that is a difference between the voltages at two different points. If you want to see what the voltage drop across a resistor is, for example, you need to put one probe of the voltmeter on one side of the resistor and the other probe on the other side of the resistor. That setup is simply called being in parallel.Voltage is potential difference between two points, hence measured across or in parallel, where as current is measured in series since current flows (*)
What storage requires a continuous flow of electronic current in order to retain its data?
RAM requires a continuous flow of current to retain data.
How do you connect voltmeter and ampermeter in the curcuit?
Originally Answered: How should an ammeter be connected in a circuit to correctly read the current? Let’s consider DC based circuits first. Ammeters then are connected in series (like in a sequential chain) between the power supply or source (not necessarily the same) and the power drain (or the circuit load). Since we are talking about a DC circuit, the power to the circuit is first turn OFF to prevent sparking (in a large current situation) and to allow the measurement driven modification to be made. I usually measure if any voltage is present at the power leads where the current measurement will be done. The reason for this is to see if there are any sneak power circuits feeding the circuit under test. The circuit is then broken (or opened with either a switch, a jumper plug removal or simply disconnected) on the (usually) positive side of the supply. If you have to physically cut the positive feed wire, make sure that you can reconnect it so that no short exposed wires remain after the measurement. Make sure that you use an ammeter that will be able to appropriately measure the load. As an example if you are trying to measure a current with a supply current in the range of 7.5A, connecting an ammeter that is designed to measure 0 to 1A, then the instrument will most likely burn out. Professionals use ammeters that have switched multiple current range or are using measuring meters that can be shunted with the appropriate range shunt. The meter positive connection (usually a red wire or probe) is connected to the positive source of the power supply. The negative wire or probe (usually a black wire) is connected to the power load (where the circuit was cut/interrupted or disconnected previously. Assuring that everything is done properly, then depending on the meter used turn the power supply on again. As a note if you are using a digital multi-meter, the instrument should be turned on FIRST, perhaps set on the highest current range. Turn the power supply back on and observe the current indication on the meter. As mentioned by other fellow Quorians, if using a current probe, then it is easier but less flexible. For AC based circuits, there are no polarities to worry about but the range issue has to be factored in. The rest is more or less the same procedure. I have been doing electronics, measurements plus remote customer support to solve power supplies issues over the phone for many years and I have seen (and experienced) my share of mishaps, errors, absence of knowledge/hands-on experience. I have seen accidents (some life threatening) so I am sharing a thing or two to help
Why ohmmeter cannot read the resistance value when current flows through resistor?
An ohmmeter works by sending a DC voltage through the load under test and measuring the current passed. This works from Ohm's law E/R=I, so, for example, a meter with a source E=9v measuring a 10kΩ resistor would sense 0.0009 Amps (or 900µa) passing through the resistor. If there is some other current being passed through the resistor at the same time, there is no way for the meter to accurately account for this current which would be added to (or subtracted from) the sense current supplied by the meter. (This is an oversimplification since the Ohmmeter will actually provide a current-limited voltage source and must account for the series resistance of the meter (in the case of an analog electro-magnetic meter), current-limiting circuit, internal resistance in the meter batteries (if applicable), etc. in order to generate an accurate reading, however, the above describes the general theory of operation).
What is the reason of connecting shunt parallel to galvanometer?
to reduce the flow of current & keeping the current through galvanometer within safe limits.
How do I use a clamp on amp meter?
Answer 1When electrical current flows through a wire [or any conductor[, it creates an electromagnetic field which the clamp on Amp meter is disigned to detect and quantify. The meter loop is hinged and movable in order to open the loop to allow the loop to be placed "around" a single conductor. It is important that the loop be placed around only one conductor as if there is more than one wire conducting, then the fields from multiple wires will interfere with the meters ability to operate.The meter will have a switch [usually rotary] to change scales, and unless you know the approximate current flowing through the circuit, you should first set the meter to the highest current scale setting, and then switch to lower current scales until the proper one is found.
Why use AC to measure ionic conductance and why not dc current?
in order to avoid electrolysis
How a multimeter be connected in order to measure resistance?
A: A multimeter is an instrument design to measure ohms volts and amps. So to measure amps a shunt is provided to allow a sample of the current to be measured as a function of voltage.
What must pass through a coil in order to make an electromagnet?
An electrical current will cause an electromagnet to energise.
To what scale should the ammeter be set in order to read a current of 2000ma?
2000ma is equal to 2 amps. Set you meter to a current range ABOVE 2 amps.
What order do these go in milliliter meter centimeter and kilometer?
Centimetre, metre and kilometre are measures of distance in order of increasing size. A millilitre, is not a measure of distance and so cannot be compared with them.
What is necessary in order to push current through a conductor?
A difference of potential (which is measured in Volts) is needed to make current flow.
What are the advantages of micrometer?
A micrometer (device) measures distance more accurately with more precision than a vernier or a tape measure. It is much cheaper than using an electron microscope, which can measure, with calibration, a length in the order of 1E-9 meter. A micrometer (unit) is equal to 1E-6 meter.
Realation of current with power and time?
There is no direct relation of electric current and power. In order to knowhow much power (or energy) the current gives up, you must know what thecurrent is flowing through.The easiest way to describe anything through which the current is flowing isto measure and state its electrical resistance.Once you know the resistance through which the current is flowing . . .Power delivered by the current = (magnitude of the current, amperes)2 x (resistance of the path, ohms)The power is delivered continuously. Its unit is watts.Each watt of power means 1 joule of energy every second.
In measuring height which is more accurate to use the meter stick or the tape measure?
Used correctly, they can be equally accurate. Each may be better in a particular circumstance. The error in a series of measurements increases the more measurements need to be taken. So, for instance, in order to measure a 100 meter tall building with a meter stick 100 measurements must be taken. With a 50 meter measure only two measurements are taken. If the margin of error in all measurements are equal, the error using the meter stick will be about 7 times more than the error using the measure. (Why 50 times as many measurements gives only 7 times the error is the subject of another answer.) On the other hand, when measuring the overall length of an irregular object it is useful to have a rigid meterstick in order to avoid the tendency to follow the object's contour. It is best, as always, to use the right tool for the job.
