Hello readers, welcome to the new post. In this post, we will have a look at what a digital tmeter is. The voltmeter is an instrument that measures voltage between two nodes in an electrical circuit. In an analog voltmeter, the pointer moves over a scale proportional to the voltage of the circuit. In this post, we’ll cover digital voltmeters and related parameters. So let’s get started with an introduction to digital voltmeters.
Introduction to Digital Voltmeters
A voltmeter is a device that is used for measuring the potential difference between two points. The voltage measured can be AC or DC. Two types of voltameters are normally used: analog and digital. An analog voltmeter comes with a dial and a needle-moving accordion to measure and show value. Analog meter replaced with a digital voltmeter based on features. Digital voltmeter shows the value of AC or DC voltage measured in discrete numbers, then pointer deflection on a continuous scale as shown in analog.
The high-accuracy digital voltmeter has input resistance in the range of one gigaOhm or higher for minimum voltage level, while the less-accurate DVM has an input range value of 10 megaOhm.
What is a voltmeter?
The voltmeter, also called the voltage meter, is a device that measures the voltage or potential difference between two points of the circuit. Normally, a voltmeter is employed for AC current measuring or or circuits. Radiofrequency voltage is also used for measuring with specialized voltmeters.
How Does a Digital Voltmeter Work?
- In its working principle, the input signal is given as input to the pulse generator. The pulse generator produces rectangle-shaped pulses having the same width as the input signal.
- The output of the pulse generator works as input for the AND gate, and another input of this gate is a pulse series. It makes a positive-triggered switch, resulting in a triggered sequence of pulses with the same width as the produced pulse of the pulse generator.
- The output of the AND gate that is positively triggered pulses is given to the inverter that inverts the output of the AND gate.
- The output of the inverter is given to the counter at the input point that counts total pulses and the duration between pulses.
- in the last accurate output is shown on LED, and the reading value in volts is shown.
Digital Voltmeter Block Diagram
The voltmeter measures voltage values in volts, millivolts, and kilovolts. For measuring voltage, a voltmeter is connected with the parallel combination. This configuration is used since the same voltage exists in a parallel combination.
The voltmeter also comes with a high value of inner resistance. It is added since it is used for measuring the potential difference between the circuit’s two points. The current of measuring devices is the same. In simple words, the high resistance of the voltmeter impedes the current flow. It helps to get an accurate value of voltage.
The main parts of a digital voltmeter are:
Output Signal
It is an input signal that is used to measure the voltage level.
Pulse Generator
It is a voltage source that is operated with AC, DC, or both ways to provide output in a rectangle shape. The level of frequency and width of the rectangle pulse produced can be regulated with the use of a digital circuit existing in the generator. Rise and falling time is configured with an analog circuit.
AND Gate
The output of the AND gate is HIGH if both inputs are high. If a train pulse with a rectangle pulse is given as input to an AND gate, then the output has a shape, and then train pulses come at the same time as the rectangular pulse.
Decimal Display
It used to count the number of impulses and the time delay between pulses. The counted results are shown on an LED or LCD screen.
Analog Voltmeters vs. Digital Voltmeters
Display Method:
- An analog voltmeter displays measured voltage with the use of a needle or scale. The position of the needle shows the measured voltage value.
- A digital voltmeter shows voltage in a numerical display. Voltage is shown in digits and easily seen on a digital display.
Sensitivity:
- Analog voltmeters come with less sensitivity than digital meters. So not good for accurate measurements.
- The digital meter has high sensitivity and is best for an accurate result.
Speed:
- An analog meter is slower for tracking fast changes in calculated voltage than a digital meter.
- Digital meter quickly responded with fast changes in voltage and provided fast results.
Reading:
- For reading the values in an analog meter, there is a needle or indicator used, which makes it difficult to find values.
- The digital meter offers direct numerical display, and reading can easily be read.
Power Consumption:
- The analog meter uses less energy and does not need a battery. There is energy efficiency and it does not affect the battery operating cycle.
- Digital meters operate on battery or external power supply and use high energy.
Cost:
- Analog voltmeters are higher in cost than digital voltmeters.
Types of Digital Voltmeters
Ramp-Type Digital Voltmeter
This meter circuit produces an output signal in a ramp shape. Volterme is used for measuring such ram signal called Ramp type digital voltmeter. Timing is important for these signals, this meter name, due to the measuring ramped-up signals.
In this meter, voltage is measured by giving an unknown input signal to range and attenuation. Based on requirements, the signal is attenuated by amplification. The ramp generator generates a positive or negative ramp, and the unknown signal is compared with it. The comparator compares the input signal with the ramp signal. If the input voltage is the same as the ramp voltage, then the gate is opened through the pulse, and then the ramp signal becomes zero, and the gate is closed. The time between two occurrences is known as a gating time interval.
Integrating-Type Digital Voltmeter
This meter measures the accurate value of input according to constant time. This circuit normally uses a voltage-to-frequency converter device that operates on a feedback control system. The main feature of this device is that output from the integrator is compared with the fixed-level voltage used as a reference.
Dual-Slope Digital Voltmeter
It gets input voltage by integrating the input signal for a certain duration in one direction and then for the same duration in the opposite direction. By comparing the 2 integrator output values, it measures the input voltage.
Successive Approximation Digital Voltmeter
In this meter, the output of the digital-to-analog converter is taken with a certain unknown reference voltage. This meter can measure about 100 readings in one second. The voltmeter uses an amplifier for the selection of the required input voltage range and reduces noise that can cause distortion.
Applications of Digital Voltmeters
- It is part of labs and laboratories for measuring correct voltage value over different devices like resistors, diodes, and capacitors.
- It is also used to measure unknown values. It helps to measure voltage, and when the voltage level is known, we can measure the current in the circuit also.
- It is used for verification purposes, such as in cathode ray tubes for verification of accurate values. It helps with circuit inspection.
- With the use of the tree ammeter technique, a 3-volt meter is used for measuring power. It is used for measuring power factor at a certain load.
- It is used for prototype and circuit design. That helps to measure and verify voltage at different points.
Symbol of Digital Voltmeter
The horizontal line with a V-shaped move to the left side is a symbol of a digital voltmeter. V is used for the notation of voltage.
Digital Voltmeter Advantages
- It does not measure reading with a pointer; it reduces the chance of human error that is due to reading at an angle. It is a gross error and removed by giving accurate results.
- It is a more reliable and stable device than an analog meter that is unreliable for measuring values.
- Its output is given to memory devices for storage use. It means we can store results obtained from the digital meters in flip-flops.
- It does not need any extra manuals for the use of the meter since it easily gets and checks
- It is more durable than an analog meter and has correct readings without affecting different factors like atmosphere, temperature, and moisture.
Disadvantages of Digital Voltmeters
- It is more fragile than an analog meter and requires handling properly. It can get heated for long use and also has a chance of wrong reading.
- Its speed is based on a digitizing circuit. It can minimize the operational speed of the voltmeter for reading.
- There is a certain threshold value for a digital meter, and crossing that value can affect the meter.
- If there is a fluctuation in the output, the digital meter does not measure them and provides incorrect values for output.
- Its design is such that it does not measure transient voltage with the use of the device. So measuring transient spikes in this meter is not easy.
Read our latest Electronic Guides:
What is a 12V digital voltmeter gauge?
- This voltmeter measures DC voltage from 8V to 16.0V.
- It comes in a mini size with a 3-digit LED digital display.
- It can easily connect and has waterproof features. It can connect with the battery to show real-time data of current voltage. The positive pole is connected with a red wire and the negative pole with a black wire. The power cord is about 100 cm long.
- It displays LLL when the voltage is less than the measuring range and HHH when the voltage is higher than the measuring range.
- It is commonly used for cars, bikes, motorcycles, substation automation, testing instruments, etc.
What is the symbol of the voltmeter?
Voltemteer is denoted with the letter V in a circle, having two emerging lines denoting 2 points of calculation.
What are the 2 types of digital voltmeters?
- 1) Ramp type DVM:
- (2) Integrating type DVM:
- (3) Potentiometric type DVM:
- 4) Successive Approximation type DVM:
- 5) Continuous Balance DVM
How does a voltmeter work?
DC Voltmeter and Ammeter in Proteus
The voltmeter measures the value of voltage passing between two points. It performs this operation by measuring the difference between positive input voltage and negative input voltage.
A voltmeter is normally used for measuring the power of a circuit.
A voltmeter comes with 3 parts:
- Positive input terminal
- Negative input terminal
- Display,
Before using a voltmeter, define whether the current under measurement is direct current or AC. Ensure that you use a meter that supports the type of current under measurement.
Select the dial to a range of voltage you are measuring.
- Connect the positive input terminal pin with a positive point of the circuit.
- Connect the negative input terminal pin with the negative end of the circuit.
What are the types of voltmeters?
Permanent magnet moving coil voltmeter (PMMC):
This meter measures the current in the coil by measuring the angular deflection of the coil in a uniform magnetic field called a permanent magnet moving coil (PMMC) voltmeter; another name is the D’Arsonval meter or simply galvanometer. The value of measured voltage induces current in PMMC instruments that move the pointer.
Moving iron voltmeter:
This meter is used to measure both AC and DC voltages. The deflection of the meter is proportional to the coil voltage. It also has two types of attraction: moving iron voltmeter and repulsion moving iron voltmeter.
Electrodynamometer-type voltmeter:
- The voltage of both AC and DC circuits was measured with the use of this meter, and the same method was used for AC and DC values.
Rectifier-type voltmeter:
- It is used for measuring the voltage of AC circuits. It converts AC to DC through rectifiers.
Electrostatic-type voltmeter:
A static electrical field produces deflection torque. Many meters are used for measuring high voltage.
What is the SI unit of the voltmeter?
The SI unit of potential difference is the volt.
What is the formula for a voltmeter?
The formula for a voltmeter is:
V = I * R
where:
- V is measured voltage.
- I is current in a meter
- R is the resistance of the voltmeter.
What is an analog-to-digital al converter? How is it similar to DVM?
The analog-to-digital converter is used for the conversion of the analog signal into a digital signal with the use of circuits. Its working is like DVM since it converts analog input signals into a sequence of pulses.
What is the range of digital voltmeters?
The range of input voltage is from 1 to 1000 volts. It comes with an automatic range or an overload indication.
What are the characteristics of a digital voltmeter used in a typical digital multimeter?
The digital voltmeter is a voltage-measuring device, and when used in any device, it has a voltage reading in number form without the use of a pointer.
FAQs
Q1: Are digital voltmeters more accurate than analog voltmeters?
Digital multimeters are more accurate, easy to read, and come with more features and functions than analog meters.
Q2: Can we use a digital voltmeter to measure current and resistance?
Normally, a voltmeter is a function of a multimeter, which is an electrical instrument having features to measure voltage, current, and resistance.
Q3: What is the advantage of using a digital multimeter instead of a standalone digital voltmeter?
The main advantage of the digital multimeter is its versatile feature. It helps us to measure different electrical parameters with a single device, saving time and energy, and also offers detailed results.
Q4: Can digital voltmeters measure both AC and DC voltages?
The digital voltmeter is configured to read DC or AC voltage, current, resistance, or other physical properties, provided that a proper transducer is inserted.
Q5: Are digital voltmeters suitable for high-frequency voltage measurements?
The electrostatic instruments use static electric fields to generate deflection torque. These instruments are used for the measurement of high voltages.
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