Definition: The galvanometer which is used for estimating the quantity of charge flow through it is called the ballistic galvanometer. The working principle of the ballistic galvanometer is very simple. It depends on the deflection of the coil which is directly proportional to the charge passes through it. The galvanometer measures the majority of the charge passes through it in spite of current. The ballistic galvanometer consists coil of copper wire which is wound on the non-conducting frame of the galvanometer. The phosphorous bronze suspends the coil between the north and south poles of a magnet.
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Definition: The galvanometer is the device used for detecting the presence of small current and voltage or for measuring their magnitude. The galvanometer is mainly used in the bridges and potentiometer where they indicate the null deflection or zero current. The potentiometer is based on the premise that the current sustaining coil is kept between the magnetic field experiences a torque. The moving coil, suspension, and permanent magnet are the main parts of the galvanometer.
It is rectangular or circular and has the number of turns of fine copper wire. The coil is freely moved about its vertical axis of symmetry between the poles of a permanent magnet. The iron core provides the low reluctance flux path and hence provides the strong magnetic field for the coil to move in. The other current carrying coil is the lower suspension whose torque effect is negligible. The upper suspension coil is made up of gold or copper wire which is made in the form of a ribbon.
The mechanical strength of the wire is not very strong, and hence the galvanometers handle carefully without any jerks. The beam of light placed on the scale on which the deflection is measured. The galvanometer is used as an ammeter by connecting the low resistance wire in parallel with the galvanometer. The potential difference between the voltage and the shunt resistance are equal. As the galvanometer and the shunt resistance are connected in potential with the circuit, their potentials are equal.
Thus, the shunt resistance is given as,. The galvanometer is used as a voltmeter by connecting the high resistance in series with the circuit. The range of the voltmeter depends on the value of the resistance connected in series with the circuit. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Circuit Globe All about Electrical and Electronics.
Electronic Instrumentation. Circuit Globe Electrical Measurement Galvanometer. Good observation. It should be high resistance for Voltmeter and Low resistance for ammeter. Leave a Reply Cancel reply Your email address will not be published.
In this article, we shall study principle, construction, working, sensitivity and accuracy of the moving coil galvanometer. When a current-carrying coil is suspended in a uniform magnetic field it is acted upon by a torque. Under the action of this torque, the coil rotates and the deflection in the coil in a moving coil galvanometer is directly proportional to the current flowing through the coil. The suspended type consists of a rectangular coil of thin insulated copper wires having a large number of turns.