Operation of PMMC Instrument Most analogue (pointer-on-scale) instruments rely on three factors for their operation: a deflecting torque; a restoring torque; and a damping torque. Deflecting Torque: Essentially, a moving coil meter is a current measuring device. The current to be measured is passed through a multi-turn coil suspended between the poles of a permanent […]
Ammeters and voltmeters affect the operation of circuits. The degree to which the circuits are affected is called the loading effect of the instrument. For an instrument to provide an accurate indication of how a circuit operates, the loading effect should ideally be zero. In practice, it is impossible for any instrument to have zero
The three most commonly used electrical test instruments are: the clamp-on amp meter, the AC voltmeter, and the Ohmmeter. These three meters are commonly known today as digital multimeters (DMM). It is vitally important that electrical personnel know how to correctly use a DMM. These meters are used to not only understand how an electrical
Electrostatic voltmeters are based on the fact that an electric force (attraction or repulsion) exists between charged plates or objects. An electrostatic voltmeter is essentially an air condenser ; one plate is fixed while the other, which is coupled to the pointer, is free to rotate on jewelled bearings. Electrostatic Voltmeter Working Principle When p.d.
Hi friends, in this article, I am going to discuss about the lux meter working principle and its application. We have to measure light in many tasks. For this, the Lux meter should be used. To measure the light accurately, a lux meter is a very suitable device. It is calibrated to read directly in lux. The
Hi friends, In this article, I am going to discuss the thermocouple instrument working principle, its types and applications. So let us start with our topic. When two metals of different work functions are placed together, a voltage is generated at the junction. This generated voltage is proportional to the temperature and this junction is known as
Hi friends, In this article, I am discussing the moving coil galvanometer working principle, its construction and conversion into voltmeter and ammeter. So let us start our topic. A moving coil galvanometer is an easy and sensitive instrument to detect and measure electric current. Galvanometer Working Principle The working principle of galvanometer is based upon the
Hi friends, in this article, I am discussing about analog frequency meter working principle and hope you will find it informative and helpful. The action of moving iron analog frequency meter depends on the variation in current drawn by two parallel circuits – one inductive and the other non-inductive – when the frequency changes.
A mechanical resonance type frequency meter indicate the supply frequency of the circuit directly and is very much convenient for most practical purposes. It is a very simple instrument and has got an advantage of giving reading free from errors due to change in temperature, waveform and magnitude of applied voltage. Construction of Mechanical Resonance Type
The power factor of a circuit can be found from the wattmeter reading and voltmeter and ammeter readings suitably connected in the circuit. Power factor = Wattmeter reading ÷ (Voltmeter reading x ammeter reading). Power factor = True Power ÷Apparent Power This method involves mathematical calculations. Sometimes it is required to measure the power factor of the