Tag: Electrical measurements
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Basic Elements of an Electronic Instrument
An electronic instrument is made up of the following key elements: Transducer This is the first sensing element and is needed only when measuring a non-electrical quantity such as pressure or temperature. Its task is to convert the non-electrical physical quantity into an electrical signal. An example of a transducer is a thermocouple for sensing…
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Electrical vs. Electronic Instruments
Despite the fact that both electrical and electronic instruments measure electrical quantities like voltage and current, they differ from each other in terms of the built-in features; for example, purely electrical instruments don’t possess any in-built amplifying device to increase the amplitude of the quantity being measured whereas electronic instruments typically incorporate an amplifier. DC…
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Basic Features of a DC Potentiometer
A potentiometer is an instrument that is used for measurement of potential difference across a known resistance or between two terminals of a circuit or network of known characteristics. A potentiometer is also used for comparing the emf of two cells. A potentiometer is widely used in measurements where the precision required is higher than…
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How to calibrate a dc voltmeter
An instrument may be calibrated by comparing its reading with that of a more accurate instrument when both are measuring the same quantity. The more accurate instrument is used as a standard for comparison purposes. The figure below illustrates the method for calibrating a dc voltmeter. An appropriate dc voltage level is applied from the…
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Features and Applications of Instrument Transformers
Instrument transformers are used in the measurement of voltage, current, energy, and power in ac circuits. The main reasons why instrument transformers are employed in measurements are: In power systems, the levels of currents and voltages handled are very high, and therefore direct measurements with conventional instruments is not possible without compromising the operator safety,…
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RF Power and Voltage Measurement
RF system’s output power level is often the key factor in the design and ultimately the performance of virtually all radio frequency and microwave equipment. For the measurement of average power, a sensor along with a calibrated power meter is connected with the RF transmitter. Initially, if the output of the sensor is switched OFF…
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Digital vs. Analog Instruments
Electronic instruments mainly voltmeters used either transistor or vacuum tubes. The later one is called The Vacuum Tube Voltmeter (VTVM) and the former one is called the Transistorized Voltmeter (TVM). In almost every field of electronics, VTVMs have been replaced by TVMs because of their numerous advantages. In TVM, due to the absence of a…
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Power Measurements in DC Circuits
Measurement of electric power is essential in both commercial industrial applications and domestic applications. Prior estimation and subsequent measurements of instantaneous and peak power demands of any installation are mandatory for design, operation and maintenance of the electric power supply network feeding it. How Power Measurements in DC circuits are done using an Ammeter and…