Galvanometer to Voltmeter Question

In summary, the conversation discusses constructing a voltmeter using a galvanometer with a coil resistance of 50 ohms and deflection of 3.5 mA for full scale. The question is asking for the series resistance needed to achieve a full scale deflection of 35 Volts. The solution to this problem involves reading the sections on ammeters and voltmeters, as well as capacitors in parallel. The net capacitance of a network of capacitors in parallel can be calculated by adding the individual capacitances. To find the voltage across each capacitor, the total voltage should be divided among the capacitors based on their individual capacitances. The maximum voltage that the coil can tolerate should also be taken into consideration when determining
  • #1
physics_girl
4
0
A galvanometer of coil resistance 50 ohms deflects full scale for a current of 3.5 mA. What series resistance should be used with this galvanometer to construct a voltmeter which deflects full scale for 35 Volts?
 
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  • #2
Welcome to the forums. There are people here who will be elbowing each other out of the way in order to help you with your problems in Physics. But first, you have to follow our guidelines.

https://www.physicsforums.com/showthread.php?t=94379

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  • #3
Capacitors in Parallel

A 9.0 microFaraday and 4.0 microFaraday are connected in parallel, and this combination is connected in series with 12.0 microFaraday capacitor.

1. What is the net capacitance?
2. if 32 V is applied across the whole network, calculate the voltage
across each capacitor.
 
  • #4
These two questions are the only two in my assignment that I don't know how to approach. I would appreciate some guidance as to how to begin.
 
  • #5
Begin by opening up the textbook and reading the section on ammeters and voltmeters.
Hint: current of 3.5 mA, voltage 35 V, resistance ?
Then read the section on capacitors in parallel.
 
  • #6
my partial solutions are too long to type out...
anyways, here is what I have so far... I know its incorrect because it does not differentiate between the Voltage in V=IR and the voltage I need to obtain in the question, the 35.0V...

the text says little to do this problem, it does however mention the maximum voltage the coil can tolerate.. and is also stated in units of Ohms/Volts...which I am not given in the question...

so...this has been my attempt so far...I don't really know how to proceed...
 
  • #7
Answer the question contained in my hint.
 

FAQ: Galvanometer to Voltmeter Question

1. What is a galvanometer and how does it differ from a voltmeter?

A galvanometer is a sensitive instrument used to detect and measure small electric currents. It works on the principle of electromagnetic induction and typically has a coil of wire suspended in a magnetic field. A voltmeter, on the other hand, is a device used to measure the potential difference, or voltage, between two points in an electrical circuit. While both instruments measure electrical currents, a galvanometer is more sensitive and is typically used in scientific experiments and research, while a voltmeter is used for general circuit analysis and troubleshooting.

2. How does a galvanometer work?

A galvanometer works by using a magnetic field to deflect a coil of wire, which is connected to a needle or pointer. When an electric current passes through the coil, it interacts with the magnetic field and causes the coil to rotate. The amount of rotation is proportional to the strength of the current, allowing the galvanometer to measure the current's magnitude. The direction of rotation also indicates the direction of the current.

3. Can a galvanometer be converted into a voltmeter?

Yes, a galvanometer can be converted into a voltmeter by adding a series resistor to the circuit. The resistor is used to limit the amount of current passing through the galvanometer, as it is typically designed to measure only small currents. By selecting the appropriate resistor value, the galvanometer can be calibrated to measure voltage instead of current.

4. What are the advantages of using a galvanometer instead of a voltmeter?

One advantage of using a galvanometer is its high sensitivity, which allows it to detect and measure very small currents. This makes it useful in scientific experiments and research where precise measurements are required. Additionally, galvanometers are relatively simple and inexpensive compared to voltmeters, which may have additional features and functions that are not necessary for basic current measurement.

5. Are there different types of galvanometers?

Yes, there are different types of galvanometers, including moving coil, moving iron, and electrostatic. Moving coil galvanometers use a coil of wire suspended in a magnetic field, while moving iron galvanometers use a movable piece of iron instead of a coil. Electrostatic galvanometers use electric fields instead of magnetic fields to deflect a needle or pointer. Each type has its own advantages and is used for different purposes, such as measuring different types of currents or for specific applications.

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