Galvanometer vs Voltmeter

Galvanometer and voltmeter are measuring the device which is often used to evaluate the electric circuit. The main comparison between galvanometer and voltmeter is that a galvanometer is a type of device which has parts that move in response to an electric current, while in a voltmeter is a device that is used to measure the potential difference between two points in a circuit.

What is Galvanometer?


As we know, the Galvanometer is a particular type of analogue using induction in a coil to deflect a needle against the resistance of a spring. They were often used as one component in building wider range ammeters and voltmeter.

What is Voltmeter?


A voltmeter is also known as the voltage meter. It is an instrument that measures the voltage or potential difference in voltage known as the voltmeter. As we know, The voltmeter is always connected in parallel with the circuit. Some voltmeter is intended for the direct current called as a DC circuit and other designed for alternating current called the AC circuit.
This the instrument used to measure electric potential difference or EMF between two points in an electric circuit.

Difference between Galvanometer and voltmeter:

  • A galvanometer is an instrument used to detect the flow of current in the circuit, while in voltmeter is in the instrument used to show the amount of potential difference across two points in the circuit.
  • A galvanometer tells the direction of current in the circuit, Voltmeter tells nothing about current in the circuit.
  • A galvanometer connected series in the circuit, voltmeter connected parallel in the circuit.
  • A galvanometer is a moderate resistance, While in ideal voltmeter should have infinite resistance hence the resistance of a voltmeter is very high.
  • The magnetic field is required for a Galvanometer work, Voltmeter can work with or without a magnetic field.
  • A galvanometer measure only direct current, Voltmeter tells nothing about current in the circuit.
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Advantages and disadvantages of Galvanometer

A Galvanometer is one type of ammeter. A galvanometer is an instrument for detecting and also a measuring electric current. The Galvanometer is the device that is used for measuring the magnitude of the device or detecting the presence of a small voltage(V) and current(I). The Galvanometer is mainly used in the potentiometer and bridges where they indicate the zero current or called the null deflection. Here this article gives information about the advantages and disadvantages of Galvanometer to better understand this topic.

Advantages of galvanometer:
  • It will not affect by a strong or big magnetic field.
  • It is accurate and reliable.
  • Scales of this is uniform.
Disadvantages of galvanometer:
  • Overload can spoil and kind of galvanometer.
  • We can not change the restoring torque easily.
  • The temperature change will cause a change within restoring torque.
  • These cannot be used for AC quantities measurement.
This article also gives information about moving coil Galvanometer to better understand this topic.

Advantages and disadvantages of a moving coil galvanometer:


Advantages of moving coil galvanometer:
  • High accuracy and reliability
  • The torque to weight ratio is high.
  • High sensitivity.
  • Their scale is uniform.
  • Not easily affected stray magnetic fields.
Disadvantages of moving coil galvanometer:
  • It can be used only to measure direct currents.
  • Develops errors due to factors like aging of the instruments, permanent magnets and damage of spring due to mechanical stress.
  • The change in temperature causes a change in restoring torque.
  • Restoring torque can not be easily changed.
  • Such an instrument can be used only measurement direct current quantity and can not be used for measurement of alternating current quantities.
  • There are possibilities of damage to phosphor bronze fiber or helical restoring spring due to severe stress.

Application of Galvanometer

A galvanometer is used for detecting and measuring electric current. The most common use of galvanometers was as instruments use an analog measuring instrument called as ammeter used to measure the direct current an electric circuit. Here this article gives what is the applications of Galvanometer to better understand this topic.

Uses of Galvanometer:

  • It is used for measuring the current.
  • The voltage between any two points of the circuit is also determined through the galvanometer.
  • It is used for detecting the direction of current flow in the circuit.
  • It also determines the full point of the circuit. The null point which means the situation in which no current flows through the circuit.
  • They are used in a film camera to get the reading of photoresistors in the metering mechanisms.
  • They are used in CD/DVD played and hard drives for controlling the position of head servos.
  • They are used in the control system, laser engraving, laser TVs, laser sintering, of head servos.

Why is Voltmeter connected in Parallel?

As shown in the figure, a voltmeter is connected in parallel with circuit elements because it is used to measure the voltage of the device. So important is that because elements in series have a high potential difference and high internal resistance. The amount of current passing through very less. Therefore the current through the circuit is unaltered. 

Parallel Connection
          Parallel Connection



If the voltmeter is connected in series with the circuit, it will change the potential difference which will minimize the current in the circuit as it has very large resistance and you will get faulty reading. Thus the disturb the reading of the voltmeter.




Why voltmeter has high resistance?

Voltmeters supposed to have infinite/very high resistance to avoid loading effect. The voltmeter is constructed with very high internal resistance the reason of that it measures the potential difference between the two points of the circuit. At that time, the voltmeter does not change the current of the measuring device.

 If we consider the resistance of the voltmeter won't be high, it would draw some current and the other resistors connected in parallel with it will not get enough current through them.

If the voltmeter considers being to be low resistance the current passes through it, and the voltmeter gives the incorrect or wrong result. The high resistance of the voltmeter does not allow the current to pass through it and thus that time the correct reading is obtained.

What is voltmeter?

Definition of voltmeter?


A voltmeter is also known as the voltage meter. It is an instrument that measures the voltage or potential difference in voltage known as the voltmeter. As we know, The voltmeter is always connected in parallel with the circuit. Some voltmeter is intended for the direct current called as a DC circuit and other designed for alternating current called the AC circuit.

It works on the basic principle that the torque deflects the pointer of the instrument. Thus defection of the pointer is directly proportional to the potential difference between the points.

Symbolic represantation of voltmeter?


Voltmeter symbol
Voltmeter symbol


Type of voltmeter:


Voltmeter types
Voltmeter types 


1. Classification  on the basis of Output:


  • Analog voltmeter 
The analog voltmeter uses for measuring the AC voltage. An analog voltmeter consists of a sensitive galvanometer in the series with high resistance. In this type, the internal resistance of a voltmeter must be high. The sensitivity of the galvanometer and the value of the series resistance determine the range of voltage that the meter can display.


  • Digital voltmeter 
The voltmeter which displays the values or reading in the numeric form is known as the digital voltmeter. The digital voltmeter gives an accurate result.

2. Classification on the basis of construction

  • Rectifier type voltmeter 
This type of instrument is used as the AC circuit for voltage measurement. The rectifier instrument converts the AC quantity into the DC quantity with the help of the rectifier. And this can the DC signal is measured the PMMC instrument.
  • MI voltmeter
MI instrument means that moving iron instrument. It is used for both AC and DC measurements, just because the deflection proportional to the square of the voltage assuming impedance of the meter to constant, so whatever is the polarity of the voltage it shows directional defection.

The moving iron instrument is classified into two categories:
  • Attraction type moving iron instrument
  • Repulsion type moving iron instrument
  • PMMC voltmeter


This voltmeter can work on the principle that the current-carrying conductor placed in the magnetic field and because of the current force acting on the conductor. The current induces in the PMMC because of the measured voltage, and this current deflects the pointer of the meter.



3. Classification on the basis of Measurement 

The voltmeter which measures the direct current is known as the DC voltmeter and is used in the AC circuit for alternating voltage measurement called  AC voltmeter.

 Explore more information:
  1. Why is Voltmeter connected in Parallel?
  2. Why voltmeter has high resistance?
  3. Advantages and disadvantages of digital voltmeter
  4. Advantages and disadvantages of digital voltmeter over Analog voltmeter
  5. Difference between digital voltmeter and analog voltmeter
  6. Difference between Galvanometer and voltmeter

Advantages and disadvantages of digital voltmeter

The Digital voltmeter displays the voltage readings of a circuit numerically. It measures AC or DC voltage and displays the value directly in numeric form instead of pointer reflection. A Digital voltmeter was introduced which gives the numerical display of voltage with accuracy. This article gives information about the advantages and disadvantages of digital voltmeter to better understand this topic.

Advantages of digital voltmeter:

  • Digital voltmeter is more stable and reliable.
  • The digital display of the output eliminates the human reading error.
  • A Digital voltmeter is void of parallax errors.
  • Digital voltmeter has an automatic range selection.
  • A Digital voltmeter provides better resolutions.
  • It is a smaller size and cost-effective.
  • DVM can measure both AC and DC voltages.
  • Reading is accurate and fast compared to an analog meter.
  • Latest DVM is built with a microcontroller that stores the readings for further processing.
  • The range can be taken very fast.
  • Various processing features available like RMS, peak capture, relative offset, dB, Time averaging, etc.

Disadvantages of digital voltmeter:

  • Digital voltmeter is prone to damage if the voltage is increased beyond the limit.
  • It is very hard to spot the transient voltage spikes.
  • The Analog to digital converter has a limitation on word length which causes quantization noise giving rise to errors in measured values.
  • This display depends on the external power source or the battery.
  • The speed of operations is limited due to the digitizing circuit in digital voltmeters.
  • When a fluctuation occurs in a circuit the digital voltmeter cannot read and display an error.
  • While measuring the voltage, there are chances of the digital voltmeter getting the heated up. This might output the wrong readings.
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Difference between digital voltmeter and analog voltmeter



What is an analog voltmeter?

Analog voltmeter is a move pointer across a scale in proportion to the voltage of the circuit.

 What is a digital voltmeter?

With the time an analog voltmeter is replaced by digital voltmeter due to the same advantages associated with digital systems. Digital voltmeter gives a numerical display of voltage by the help of an analog to digital converter. 

The main comparison between analog voltmeter and a digital voltmeter is that digital voltmeter electronically displays results on an LCD screen while in we are using analog voltmeter gives the reading by moving a needle across a printed background of possible results.

The main key difference between analog voltmeter and digital voltmeter are listed below:


  • In Digital voltmeter the output signal is represented in the form of digital. While in analog voltmeter the output signal representation is done by using potentiometric deflection.
  • Digital voltmeter is two types: Ramp type and integrated type while in analog voltmeter are three types: Average reading, true RMS reading, sampling type, etc.
  • Digital voltmeter has an overload indication, an analog voltmeter has no overload indication in analog voltmeter. 
  • In a digital voltmeter has better resolution compared to an analog voltmeter.
  • A digital voltmeter can be programmed, Analog voltmeter cannot be programmed.
  • Sensitivity is more in digital voltmeter compare to an analog voltmeter.
  • Digital voltmeter has a speed of operation is more Burt in analog voltmeter the speed of operation is less.
  • While we are using digital voltmeter the digitization of signal is required while in analog voltmeter is not require digitization of signal.
  • The more number of measurement range while using digital voltmeter compared to an analog voltmeter.

In this theory, we have to discuss the difference between an analog voltmeter and a digital voltmeter. I hope by reading this article you have to gain some basic information about this article. If you have any queries regarding this article or to implement any electronics or electrical project please feel free to comment in the below section.

 Explore more information:

  1. Difference between potential difference and EMF
  2. Difference between ammeter and voltmeter
  3. Difference between ammeter and ohmmeter
  4. Difference between galvanometer and ammeter 
  5. Difference between analog voltmeter and digital voltmeter
  6. Difference between DC voltmeter and AC voltmeter

Advantages and disadvantages of digital voltmeter over analog voltmeter

Whenever you measure electrical equipment, you will need a meter that can measure volts, amperes, and ohms. Most meters can do all three and have a voltmeter, ohmmeter and ammeter for features uses. However, there are two kinds of meters: Analog and digital. Here this article gives the advantages and disadvantages of digital voltmeter over analog voltmeter to better understand this topic.

There are some advantages and disadvantages of digital voltmeter over an analog voltmeter are listed below :


Advantages of digital voltmeter:
  • A digital voltmeter gives good stability.
  • Digital voltmeter has an automatic range selection.
  • A digital voltmeter can be programmed so controlling by computer is achieved.
  • It provides a better resolution.
  • It has a high speed.
  • It is bipolar.
  • It is auto-ranging.
  • Extremely high input impedance.
  • The internal calibration does not depend on o the measuring circuit.
  • Reading can be taken very fast.
  • Digital voltmeter has an automatic range selection.
  • No moving part extremely rugged and able to be made impervious to drops and shock and vibration encountered with rough use handling.
  • Overrange protection.
Disadvantages of digital voltmeter:
  • It gives some extra feature are expensive.
  • This voltmeter is usually very hard to spot transient voltage spikes, etc.
  • The speed of operation is limited due to the digitizing circuit.
  • While we have to use the display depends on the external power source or battery.
  • Digital voltmeters are prone to damage if the voltage is too much increased beyond the limit.
  • It is very to spot the transient voltage spikes.
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Difference between galvanometer and ammeter | Galvanometer vs Ammeter

What is Galvanometer?

The galvanometer uses a moving coil which is free to rotate between the permanent magnet. When the current flows through the coil, it becomes deflected and that produces the deflection of the coil is directly proportional to the current flow through it. At that time the galvanometer is converted into the ammeter by connecting the resistance in parallel with the circuit and if the resistance is connected in series with a galvanometer then it is used as a voltmeter.

What is ammeter?

The ammeter is also known as the ampere meter. The ampere is the unit of the current, so the ampere meter is the type of meter which measures the magnitude of current passes through it. It is connected in series wit circuit for determining the exact value of the circuit current. 


The main comparison between these two that the galvanometers and ammeter are that the galvanometer show both the direction and magnitude of the current, While the ammeter only shows the magnitude of the current. The other main key difference between galvanometer and ammeter are listed below

The main key difference between galvanometer and ammeter:

  • The accuracy of the galvanometer is less than the ammeter.
  • The sensitivity of the galvanometer is much more as compared to that ammeter.
  • The magnetic field is required for the working of the galvanometer whereas it is not essential fo the ammeter.
  • The galvanometer is a mechanical device that is used for determining the magnitude as well as the direction of the current while in the ammeter is the electric device which is used for measuring the magnitude of the current.
  • The galvanometer shows the direction of current flow in the circuit whereas the ammeter measures the magnitude of current flow through it.
  • Galvanometer work with the presence of a magnetic field but in ammeter is work with or without magnetic field.
  • Galvanometer has measure only direct current but ammeter measure both direct and alternating current.
  • Galvanometer used as a potentiometer and bridge while in Ammeter used as an electrical circuit.
  • The galvanometer is mostly used in a bridge and potentiometer for knowing the zero current whereas the ammeter is directly connected in series with the circuit whose magnitude is to be measured.
  • Both connected in a series in a circuit.
  • Galvanometer has a moderate resistance while the ideal ammeter should have zero resistance, hence the resistance of an ammeter is very small.

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Selection of fuse

How to select the fuse?


  • There must be a security against tire risk when the fuse is blown.
  • Sufficient clearance between terminals.
  • It must operate when a sustained overload or short circuit occurs.
  • There should be a good insulating part for the use.
  • It should provide easy replacement of the fuse wire.
  • It should no operate under the condition of momentary overload and wiring switching surge which are experience when starting a motor and switching on transformers. capacitor etc. 

Difference between DM and ADM

What is DM?

Delta modulation is a scheme to permit the use of a simple quantizing strategy for constructing the encoded signals which are oversampled purposely, to increase the correlation between adjacent samples of the signal, as seen in the differential pulse code modulation method(DPCM).


What is ADM?

This modulation is a refined form of delta modulation. This method was introduced to solve the granular noise and slope overload error caused during the delta modulation method. This modulation is exactly similar to delta modulation except that the step size is variable according to the input signal in adaptive delta modulation whereas it is a fixed value in delta modulation.


Here this article gives the difference between delta modulation and adaptive delta modulation to better understand this topic.


Difference between DM and ADM:


  • DM stands for delta modulation while in ADM stands for adaptive delta modulations.
  • Both are used for only one bit per one sample, 
  • In Delta, the modulation step size is kept fixed and cannot be varied while in Adaptive delta modulation according to signal variations step sizes varies.
  • Complexity in implementation is simple in both systems.
  • Feedback exists in the transmitter while using delta modulation, while ADM feedback exists.
  • Both having the lowest bandwidth is required.
  • In Delta modulation quantization error and distortion is dependent on when Slop overload distortion and granular noise are present while in adaptive delta modulation Qulanatization noise is present but other errors are absent. 
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Differences Between Velocity and Acceleration

The key difference between velocity and acceleration is that velocity defines the rate with which an object varies its position. While acceleration is defined as the with which velocity of the object changes during motion.

The main key difference between velocity and acceleration are listed below:


  • Velocity implies the speed of an object in the given direction, while Acceleration implies any change in the velocity of an object with respect to time.
  • Velocity is measured in m/s while the measuring unit of acceleration in m/s2.
  • Velocity calculate with displacement, Acceleration calculate with velocity
  • The product of mass and velocity of a moving object is momentum. whereas the product of mass and acceleration gives the value of the applied force on the object.
  • Velocity is given as the ratio of change in position with time. However, acceleration is the ratio of change in velocity with respect to time.
  • Velocity is a parameter that relies on displacement and time but acceleration relies on velocity and time.
  • Velocity provide information regarding the fastness of an object moving in a specific time. An acceleration gives information about the variable velocity of the object at different time intervals.
  • The formula of velocity is displacement per time(d/t) while in acceleration velocity per time (v/t).
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STM full form

What is the full form of STM?

  • Synchronous Transport Module

What does STM mean?

STM is a module that is used in a fiber-optic network, its standard for SDH(Synchronous digital hierarchy). The transmission formate is considered for the main building block diagram for Synchronous digital hierarchies. Apart from the fact that the high rate of the signals is created by multiplexing numerous STM-1 signals, lower rate payload are also mapped into STM-1.


Advantages of digital system over analog system

Nowadays the digital system is most widely used in the system, Though the digital system is advanced, there are some advantages in digital compared to an analog system. Some of the advantages of a digital system over an analog system are listed below.

What are the digital system over an analog systems?


  • Reproductiivity of the results.
  • Accuracy of results.
  • Flexibility and functionality.
  • Ease of design: No specific math skill needed to visualize the behavior of small digital circuits.
  • Programmability.
  • Due to the integration of millions of digital logic elements on a single miniature chip forming for very low cost integrated circuits.
  • More reliable than an analog system due to better immunity to noise.
  • Speed: A digital logic integration of millions of digital logic elements on a single miniature chip forming low cost integrated circuits.

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Advantages of digital circuits over analog circuits

What are the advantages of the digital circuits over the analog circuits?

  • The Digital circuit is very accurate.
  • The Digital circuit generates a digital signal which is more reliable than analog signals.
  • Compare to the analog circuits is that signal represented digitally can be transmitted without degradation due to noise. 
  • Digital signal can be used by digital circuit components, which are very cheap and easy to produce in many components on a single chip.
  • Enables transmission of signal over a long distance.
  • Digital signal maintains its quality over long distances better than analog signals.
  • Digital signals carry more information per second than analog signals circuit.
  • Digital signal is used to construct a digital circuit since the cost of digital components is very cheap.
  • Digital circuits are easy to design and cheaper than analog circuits.
  • Digital signal faster than the analog signal.
  • The hardware implementation in a digital circuit is more flexible than analog.
  • In a digital system, a more precise representation of a signal can be obtained by using a binary digit(0's or 1's) to represent it. Each digit handled by the same kind of hardware.
  • The signal processing function such as encryption and compression are employed in digital circuits to maintain the secrecy of the information.
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Differences between Analog Circuits and Digital Circuits

What is an Analog circuit?

 The analog circuits, which operate or work with continuous-valued signals or continuously varying signals, these signals are commonly referred to as an analog signal. The Analog signal is sound, light, etc. The Analog circuit is usually much more susceptible to noise. The small changes in the voltage level of an analog signal may produce significant errors when being processed.
What is a Digital circuit? 
The Digital circuit operates or works on signals whose values exist at two levels only or has only two values the 0's ad 1's. These signals are commonly referred to as a digital signal, at any given instant of time the value of digital can be either high(1) or low(0).

The main key difference between Analog circuit and Digital circuit are listed below:

  • Analog circuits operate on continuously variable signal also known as the Analog signal while in Digital circuit operate on discreetly variable signal or digital signals. This signal existed only in two levels 0 and 1.
  • Analog signal is quite difficult to design, depending on the efficiency and precision. Digital circuit are relatively easy to design with automated tools available for various stages of design and analysis.
  • Analog circuit there is no need for data conversion, there is delay no loss of information but in the digital circuit the process of converting analog signal to digital signal, there might a significant amount of data loss, which can result in loss of information.
  • Analog circuits can directly accept the signal from outside as the data is already analog whereas if the digital circuit has to acquire data from the physical world, the analog signals must be converted to digital signals first.
  • If the precision and accuracy are not a criterion, then analog circuits can be simple and inexpensive while in the Digital circuit is a simple design technique and also a low cost, the digital circuit provides good accuracy and precision.
  • Due to the lack of skilled engineers and the complexity of the design the analog circuits can turn out to be quite expensive, Wheres advanced integrated circuits technologies and many other factors help the digital circuits to be reliable.
  • Analog circuit are typically routine made and lack flexibility, Digital circuit has a high degree of elasticity.
  • In analog circuits, since there is no conversions involved at the input or at the output side there is no loss of information that is available for processing but in a digital circuit due to conversion process at the input side means that analog to digital and the output side, some amount of information is lost during the conversion process.
  • The manpower available to design analog circuits is very low, this results in long time to market the finished products, while in the digital circuit the available manpower to design. Digital circuits are significantly very large compared to that of analog circuit designers.
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MEMS full form

What is the full form of MEMS?

Answer:

  • Micro-Electromechanical System

What does MEMS mean?

MEMS system which allows both electronic circuits and also a mechanical device to be manufactured on a silicon chip, similar to the process used for integrated circuits. In this system the physical dimension can range from several millimeters to less than one micrometer, a dimension was many times smaller than the width of a human hair, it is a very small part. MEMS devices can vary from relatively simple structures having no moving elements to extremely very complex electromechanical systems and it using with multiple moving elements under the control of integrated some microelectronics.

Advantages and disadvantages of MEMS technology

MEMS stands for a micro electro mechanical system, It is the process of used to create tiny integrated devices or systems that combine mechanical and electrical components or devices. They are fabricated using the IC batch processing techniques and can range in the size from a few micrometers to millimeters. Now let us discuss the advantages and disadvantages of MEMS technology to better understand this topic

Advantages  or benefits of MEMS:

  • MEMS switches and actuators also can attain very high frequencies. 
  • MEMS devices require very low power consumption.
  • MEMS can be readily integrated with microelectronics to achieve an embedded mechatronic system.
  • It improved reproductivity.
  • Higher accuracy, sensitivity, and selectivity.
  • MEMS sensors possess extremely high sensitivity.
  • Extremely it scalable in manufacturing, resulting in very low unit costs when mass is produced.
  • Scaling effect at microscopic levels can be leveraged to achieve the design and dynamic mechanisms otherwise not possible at micro scales.
  • Easier to alter the part of a device as compared to its macro counterparts.

Disadvantages or drawback of MEMS:

  • Very expensive during the research and development stage any new MEMS design or devices.
  • Fabrication and assembly unit costs can be very high for low quantities. therefore, MEMS are not suitable for only niche applications, unless cost is not an issue.
  • Polysilicon is a brittle material.
  • Farm establishment requires a huge investment.
  • Prior knowledge is needed to integrate MEMS device
  • The design includes very complex procedure.
  • Very expensive upfront setup cost for fabrication cleanrooms and boundary facilities.
  • Testing equipment to characterize the quality and performance can also be expensive. 

Advantages and disadvantages of radio frequency

RD stands for Radio-Frequency, It is a rate of an alternating electric current(AC) or voltage or of a magnetic electric or the mechanical system or electromagnetic field in the frequency range from around 20 kHz to around 300 GHz. Now let us discuss the advantages and disadvantages of radiofrequency to better understand this topic.

Advantages of radio frequency (RF):

  • It is used in radar for object detection.
  • It is used for satellite communication.
  • It is used for radio and television transmission and for cellular mobile phone service.
  • It is used in the microwave line of the sight communication system.
  • It is used in various medical applications, It is used in Diathermy instrument on the frequency. It is used in MRI for taking an image of humans today. It is also used for skin tightening.

Disadvantages of radio frequency(RF):

  • The areas near RF cellular towers have been observed with more lightening compare to the other areas to be considered.
  • It also affects some of the fruits to grow ear the RF tower areas.
  • As Radio-frequency(RF) waves are available both in the line of sight as well as the non-LOS region of the transmitter, it can be easily intruded by the hackers and crucial personal/official data can be decoded for malicious motives. This signal can also be modulated either using frequency hopping or spread spectrum techniques to avoid this kind of eavesdropping.
  • Uncontrolled traditions of RF affect pre-adolescent children, pregnant women, patients with pacemakers, small birds, Flora, and fauna, etc.
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