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The term "galvanometer", in common use by 1836, was derived from the surname of Italian electricity researcher Luigi Galvani, who discovered in 1771 that electric current could make a frog's leg jerk.
The deflection of a magnetic compass needle by current in a wire was first described by Hans Oersted in 1820. The phenomenon was studied both for its own sake and as a means of measuring electrical current. The earliest galvanometer was reported by Johann Schweigger at the University of Halle on 16 September 1820. Andre-Marie Ampere also contributed to its development. Early designs increased the effect of the magnetic field due to the current by using multiple turns of wire; the instruments were at first called "multipliers" due to this common design feature.
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Why is phosphor- bronze wire used in moving coil galvanometer?
restoring torque is k theta the value of k depends upon the nature of the material used for suspension strip value of k is very small for quartz or phosphor bronze so in galvanometer phosphor bronze wire is used.
Why needle of tangent galvanometer move by increasing and decreasing current?
The galvanometer is oriented so that the plane of the coil is vertical and aligned along parallel to the horizontal component He of the Earth's magnetic field (i.e. parallel to the local "magnetic meridian"). When an electrical current flow through the galvanometer coil, a second magnetic field H is created. At the center of the coil, where the compass needle is located, the coil's field is perpendicular to the plane of the coil. These two perpendicular magnetic fields add vertically, and the compass needle points along the direction of their resultant He + H. The current in the coil causes the compass needle to rotate by an angle\ \theta.
Is galvanometer used in ac circuits if not why?
firstly a galvanometer instrument measures very small amounts of current flow of a D,C, nature / type . an a.c. type circuit is likely to be of a high magnitude , such that it would render the instrument unusable and dangerous to the operator . also a galvanometer by design is known as a moving coil type meter , if an ac signal were to be connected to this, the rate of change of the ac signal voltage would be so fast / frequent that the user would be unaware that the signal is currently changing
What is used to turn the pointer of a galvanometer?
A small current passes through the coil that actuates the pointer. When you select different ranges on the instrument you are in fact selecting different resistors so that the sensitivity of the pointer is changed.
A coil of wire connected to a galvanometer When the coil is rotated in a magnetic field the galvanometer records a current The current results because?
The creation of electric current in a conductor moving in a magnetic field was discovered by Faraday in about 1825, but he didn't know why it happened. Fundamentally, it is due to the attraction/repulsion between the magnetic field and the free electrons in the conductor, so that when the conductor moves it causes the electrons to move, which comprises the current. A similar effect can be obtained if the conductor is still and the magnetic field moves. These effects are the absolute fundamental reasons for being able to generate electricity using rotating machines, which are designed with different characteristics but all make use of the above physical facts
Can moving coil galvanometer be used to detect ac in a circuit give reason?
Moving coil galvanometer is used to detect unknown resitance of the both ac or dc circuits :)deepak instrumentation engineerAnswerA 'galvanometer' is simply an instrument that detects and measures small currents; 'moving coil' describes its operating principle. A moving-coil galvanometer is a d.c. instrument; if subject to a.c., then it will simply vibrate as it will not be able to respond the the frequency (unless the frequency is very low, in which case, it will sweep back and forth in step with that frequency).The moving-coil principle is applied to other instruments, and can be used in the construction of multimeters. In the case of a multimeter, a rectifier circuit is incorporated so that it can be used to measure a.c. currents and voltages.
What is the work of galvanometer?
Moving coil galvanometer? If so, it is effectively an electric motor acting against a spring. the force from the motor is proportional to the current and the force from the spring is proportional to displacement. When they are equal, the needle (attached to the motor), stops. Moving iron meters rely on opposite magnetic poles repelling.
State principle of moving coil galvanometer?
Principle of Working:A Moving Coil Galvanometer works on the Electromagnetic effect of current carrying coil (free to move) being placed in an air-gap between the soft iron core and the strong pole pieces of the magnet.The current following in the moving coil which is the specimen to be sensed or measured results in a generation of a Magnetic Field which is opposite to that of the fixed magnetic pole pieces. And as like poles attract each other results in a generation of small deflecting torque which further deflects the pointer or the mirror attached to the axis of the coil.Construction:Moving Coil:The Moving coil which is free to move is being suspended from a soft metallic (non-magnetic) strip carrying the current specimen which is to be sensed or measured. The Moving coil is being suspended in the air-gap available between the fixed Soft Iron-Core and the fixed pole pieces of the magnet.The Soft Iron Core is used to provide a path of low reluctance so as to focus the magnetic field generated by the fixed magnetic pole pieces towards the moving coil. The use of low reluctance Soft Iron-Core helps to increase the sensitivity of the Galvanometer as well.In many of the Moving Coil Galvanometer Construction Soft Iron-Core pieces are removed and this results in the reduction of the sensitivity of the Galvanometer as a whole. In absence of the soft fixed iron core in the middle of the coil the coil then is narrowed in order to reduce the free air space, this narrowing of the coil results in the reduction of the Moment of Inertia(MI) of the moving coil arrangement. This results in having a good near to critical damping with very less oscillations.The Moving coil consists of a large number of turns wounded on a former which can either be in rectangular or circular in shape. The current carrying coil is made up of a thin non magnetic metal so as to have low resistance and less mass.Damping:Damping in Moving Coil Galvanometer is provided by an Eddy current damping mechanism. The damping is made as such to have a nearly critical damping by setting the device to be between under-damped and critical damped case.Controlling Torque:Spring Control mechanism is largely utilized to provide the suitable controlling torque.
How is a galvanometer sensitive?
GALVANOMETER detects very small currents in terms of milli amperes so it is said to be called as sensitive
Why is phosphor- bronze wire used in moving coil galvanometer?
restoring torque is k theta the value of k depends upon the nature of the material used for suspension strip value of k is very small for quartz or phosphor bronze so in galvanometer phosphor bronze wire is used.
Why needle of tangent galvanometer move by increasing and decreasing current?
The galvanometer is oriented so that the plane of the coil is vertical and aligned along parallel to the horizontal component He of the Earth's magnetic field (i.e. parallel to the local "magnetic meridian"). When an electrical current flow through the galvanometer coil, a second magnetic field H is created. At the center of the coil, where the compass needle is located, the coil's field is perpendicular to the plane of the coil. These two perpendicular magnetic fields add vertically, and the compass needle points along the direction of their resultant He + H. The current in the coil causes the compass needle to rotate by an angle\ \theta.
How do you convert galvanometer to an ohmmeter?
"An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current."The unit of measurement for resistance is ohms (Ω).It is useful device for rapid measurement of resistance. It is consist of galvanometer and adjustable resistance Rs of known value and a cell connected in series. The resistance R to be measured is connected between the terminals.The series resistance Rs is so adjusted that when the terminals are short circuited i.e., when R = 0, the galvanometer gives full scale deflection. So the extreme graduation of the usual scale the galvanometer is marked 0 for resistance measurement. When terminals are not joined no current passes through the galvanometer and its deflection will be zero . Thus zero of the scale marked as infinity. . When R is not infinite , the galvanometer deflects to some intermediate point depending on the value of R scale can be calibrated to read the resistance directly.
Is galvanometer used in ac circuits if not why?
firstly a galvanometer instrument measures very small amounts of current flow of a D,C, nature / type . an a.c. type circuit is likely to be of a high magnitude , such that it would render the instrument unusable and dangerous to the operator . also a galvanometer by design is known as a moving coil type meter , if an ac signal were to be connected to this, the rate of change of the ac signal voltage would be so fast / frequent that the user would be unaware that the signal is currently changing
What is used to turn the pointer of a galvanometer?
A small current passes through the coil that actuates the pointer. When you select different ranges on the instrument you are in fact selecting different resistors so that the sensitivity of the pointer is changed.
What is a galvanometer?
a device designed to measure small electric currents; the simplest electric meterA galvanometer is an instrument for detecting and measuring small electric currents.Or use this long answer: galvanometer , instrument used to determine the presence, direction, and strength of an electric current in a conductor. All galvanometers are based upon the discovery by Hans C. Oersted that a magnetic needle is deflected by the presence of an electric current in a nearby conductor. When an electric current is passing through the conductor, the magnetic needle tends to turn at right angles to the conductor so that its direction is parallel to the lines of induction around the conductor and its north pole points in the direction in which these lines of induction flow. In general, the extent to which the needle turns is dependent upon the strength of the current. In the first galvanometers, a freely turning magnetic needle was hung in a coil of wire; in later versions the magnet was fixed and the coil made movable. Modern galvanometers are of this movable-coil type and are called d'Arsonval galvanometers (after Arsène d'Arsonval, a French physicist). If a pointer is attached to the moving coil so that it passes over a suitably calibrated scale, the galvanometer can be used to measure quantitatively the current passing through it. Such calibrated galvanometers are used in many electrical measuring devices. The DC ammeter , an instrument for measuring direct current, often consists of a calibrated galvanometer through which the current to be measured is made to pass. Since heavy currents would damage the galvanometer, a bypass, or shunt, is provided so that only a certain known percentage of the current passes through the galvanometer. By measuring the known percentage of the current, one arrives at the total current. The DC voltmeter , which can measure direct voltage, consists of a calibrated galvanometer connected in series with a high resistance. To measure the voltage between two points, one connects the voltmeter between them. The current through the galvanometer (and hence the pointer reading) is then proportional to the voltage.
What is galvalometer?
i think this is galvanometer so galvanometer is a device which detect the current as well as it measure small amount of current
How do you convert galvanometer to ohmmeter?
Ohms are the unit of measurement for resistance, so an ohmmeter is a device that measures electrical resistance. A galvanometer measures the current flowing through the resistance, so the two are related. To convert a galvanometer into an ohmmeter, one needs an external battery.
