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A digital voltmeter measures an unknown amount of input voltage by converting it into a digital voltage quantity and thus representing it in the digital voltmeter scale in a numeric form. Analogue voltmeters generally move their pointers across the scale with respect to the voltage a given electric circuit possesses.
The first digital voltmeter was introduced in 1954 by Andrew Kay. The measurements they show depend on a variety of factors. These factors can range from the digital voltmeter’s temperature, power supply, input impedance and much more.
The models of digital voltmeters vary according to price. The key difference which these voltmeters demarcate is the range of voltage they are able to measure. The digital voltmeters can measure up to 10 megaohms of voltage. However, the less expensive ones can only measure up to 1 megaohms of voltage.
What is The Voltmeter Symbol?
The instrument we use to determine the potential electric difference between two points in an electric circuit is called a voltmeter. The symbol we use to depict the voltmeter in the diagrams of electric circuits is a V enclosed in a circle and connected by two lines showing the two points of measurement.
Amplified Voltmeter
Sometimes we need to increase the sensitivity of a voltmeter. This can be done if the current which is required to deflect the metre pointer of a voltmeter is supplied by an amplifier and power supply instead of the circuit directly under test.
An amplified voltmeter can have various benefits such as, it can be a rugged moving coil instrument. This is because a rugged coil is less sensitive but with an amplifier, we need not use a sensitive coil. The second benefit is that since the sensitivity need not be high, the input resistance can be converted into high.
Ammeter Symbol
An ammeter is an instrument we use to measure either alternate or direct current in the unit of amperes. The symbol for ammeter in an electric circuit diagram is simply shown as a capital A inside a circle connected by the lines representing electrical wires.
In order to measure it, the ammeters must be connected to an electrical circuit. However, in the case of relatively small amounts of currents such as up to a few amperes, an ammeter may pass the whole of the circuit current. Similarly, for larger currents, a shunt resistor is used. The resistor carries most of the current and an accurate small fraction of some of the current passes through the metre movement in order to measure the amperes.
Voltage Symbol
The pressure from an electrical switch’s power source pushes charged electrons through a conducting loop and hence making them capable of doing a task such as lightening up a bulb is called Voltage.
The symbol for voltage in an electrical circuit diagram is a simple V. The term voltage and potential difference are often used interchangeably, however, the potential difference can be better defined as the potential energy difference that exists between two points in a circuit.
Multimeter Symbol
A multimeter is an instrument that is used for measuring various electrical properties such as voltage, resistance and the current in an electrical circuit. This is an integral reason why we also call multimeters volt-ohm-milliammeters. This is because the instrument of the multimeter as the name suggests is equipped with a voltmeter, ammeter and ohmmeter.
Multimeters can measure direct current voltage and alternating current (AC) voltage. It is due to this reason that they need to display more than one voltage symbol. However, in some older models, the designation for AC voltage is VAC.
These days, manufacturers find it more convenient to simply place a wavy line over the V which highlights the AC voltage. However, to signify DC voltage, the general practice is to place a dotted line and then a solid line over it above the V. You can also switch the voltage readings to get a reading in millivolts by making an adjustment through the dial and setting it to mV.
Conclusion
This article covers what the symbols for a voltmeter, voltage, ammeter and multimeter are in a given electrical circuit. These symbols are used when drawing an electrical circuit for representing working functioning instruments.
This article also explains what these instruments are used for in an electric circuit. Including the function of each instrument played and the symbols, each instrument shows its usage.
