Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

What is an Ohmmeter?An ohmmeter (also known as an ohm meter) is an instrument that measures the electrical resistance of a material (resistance is a measure of the opposition to the flow of electric current). Micro-ohmmeters (micro ohmmeter or microhmmeter) and Milliohmmeters make low resistance measurements, while Megohmmeters (a trademarked device by Megger) measure large values of resistance.Every device has electrical resistance. It may be large or small, and it increases with temperature fo

Impedance, which is having both magnitude and phase, is truly an opponent to the flow of current in AC circuits with the presence of an applied voltage.The Vector Impedance Meter is employed for measuring both the amplitude and phase angle of impedance (Z).Normally, in other measuring techniques of impedance, the individual values of resistance and reactance are obtained in rectangular form. That isBut here, the impedance can be obtained in polar form. That is |Z| and phase angle (θ) of impedanc

When we measure an electrical signal there very often may be a chance of over current through the meter. This may be due to following reasons. The meter may be connected wrongly to the circuit. The rating of the meter is selected wrongly for the measurement. Occurrences of over current in the circuit itself during measurement.Over current causes overheating in the meter which may ultimately lead to a permanent damage to the meter. The reasons of the over current cannot be avoided 100% although i

What is Voltmeter?Voltmeter is a voltage meter. Which measures the voltage between the two nodes. We know the unit of potential difference is volts. So it is a measuring instrument which measures the potential difference between the two points.Working Principle of VoltmeterThe main principle of voltmeter is that it must be connected in parallel in which we want to measure the voltage. Parallel connection is used because a voltmeter is constructed in such a way that it has a very high value of re

Introduction of AmmeterAs we know a word “meter” is associated with the measurement system. Meter is an instrument which can measure a particular quantity. As we know, the unit of current is Ampere. Ammeter means Ampere-meter which measures ampere value. Ampere is the unit of current so an ammeter is a meter or an instrument which measures current.Working Principle of AmmeterThe main principle of ammeter is that it must have a very low resistance and also inductive reactance. Now, why do we need

We have three phase system and by convention we write three phases as RYB. Phase sequence indicator is the indicator that determines the phase sequence of the three phase supply system.When we give conventional three phase supply (i.e. RYB) to the induction motor, we see that the direction of the rotation of the rotor is in clockwise direction.Now what will happen to direction of rotation of rotor if the phase sequence is reversed, the answer to this question is that the rotor will rotate in the

Before we introduce various types of power factor meters it is very essential to understand what are the needs of power factor meter? Why we do not directly calculate power factor in an AC circuit just by dividing the power with product of current and voltage because these readings can be easily obtained from wattmeter, ammeter and voltmeter. Obviously there various limitations of using this method as it may not provide high accuracy, also chances of increment of error is very high. Therefore th

The main principle of working of weston type frequency meter is that “when an current flows through the two coils which are perpendicular to each other, due to these currents some magnetic fields will produce and thus the magnetic needle will deflects towards the stronger magnetic field showing the measurement of frequency on the meter”. Construction of weston frequency is as compared to ferrodynamic type of frequency meter. In order to construct a circuit diagram we need two coils, three induct

The instruments which measure the reactive power of the circuit are called varmeter. What is reactive power? The reactive power in the circuit is given by VIsinA.Here there is no need to give an explanation about the physical meaning of reactive power, as only a mathematical relation is sufficient. Measurement of reactive power is essential because if the reactive power is more in the circuit then the electrical power factor will be poor hence losses will be more. On the basis of power supply, t

Anelectronic DC voltmeteris a device that measures the direct current (DC) voltage across any two points of an electric circuit. It is an essential tool for testing, troubleshooting, and designing electronic circuits and devices. Unlike mechanical voltmeters, electronic voltmeters use semiconductor components such as diodes, transistors, and amplifiers to increase their sensitivity and accuracy.What is a DC Voltage?A DC voltage is a constant voltage that does not change its polarity or magnitude