Can anyone explain me this circuit
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Member • May 13, 2009
This is The LVDT.
This circuit gives the Variation in output voltage according to the displacement of the Iron core (Both Primary side and Secondary side)..
Figure 1:
Here There is Mutual inductance between Coils is depend upon how much portion of the coil interacts... as shown in figure right now both secondary coils are interacted so according to that there is some induced voltage in both upper side and lower side and as they have common ref. it gives the resultant difference output.. Assume that output voltage is V0 and voltage induced in upper section is V1 for lower section V2 then Resultant output voltage is V0=|V1-V2|.
Figure 2:
Now as per the Second Figure... Sore is in Upside position so there are no same portion interacted with primary..
so there is different amount of voltage induced in both coil so V1 and V2 are Different and there should be V1<V2 or V1>V2 according to Core Position. hence the Output Voltage V0 Changes in accordance with the Placement of the Iron Core.
Hop you got the Working this is the my knowledge and in my Style.Are you sure? This action cannot be undone. -
Member • May 13, 2009
thanks a lott....[😛] 😁😁Are you sure? This action cannot be undone. -
Member • May 13, 2009
Welcome !! ErneshaAre you sure? This action cannot be undone. -
Member • Jun 5, 2009
Yep that is a L.V.D.T. (Linear Variable Differential Transformer) and Godfather beat everyone by answering it first.
Though I am around a month late but still I will add on to what Godfather has written.
The important features are that the two secondary coils are connected in series opposition. Motion of the coil up or down varies the relative flux linking the two secondary coils. Voltage induces increases in one coil and decreases in the other.
Output voltage varies linearly with displacement of core from null position.
Application
Widely used as secondary transducers for displacement measurement in a variety of applications eg. force measurement.
Main Advantages
- Electrical: Output voltage linear and is continuous function of mech. displacement, high sensitivity, low output impedance.
- Mechanical: Frictionless motion of core, negligible operating force required, can operate even at high temp., simple design and installation.
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Member • Jun 5, 2009
Well your writing skill is good... i am poor in that nice Explanation there Rajraj87verma88Yep that is a L.V.D.T. (Linear Variable Differential Transformer) and Godfather beat everyone by answering it first.
Though I am around a month late but still I will add on to what Godfather has written.
The important features are that the two secondary coils are connected in series opposition. Motion of the coil up or down varies the relative flux linking the two secondary coils. Voltage induces increases in one coil and decreases in the other.
Output voltage varies linearly with displacement of core from null position.
Application
Widely used as secondary transducers for displacement measurement in a variety of applications eg. force measurement.
Main Advantages
- Electrical: Output voltage linear and is continuous function of mech. displacement, high sensitivity, low output impedance.
- Mechanical: Frictionless motion of core, negligible operating force required, can operate even at high temp., simple design and installation.
Are you sure? This action cannot be undone. -
Member • Jun 5, 2009
Another thing the circuit in the diagram is, is a differentially capacitive/inductive set of windings on T1T2 the "transformers". equal to the outer windings with Vin Vout across each, and the inner winding.
Armature A, induces coupling of current I in each coil, since it stores magnetic 'charge' or torque as electron spin-momentum. Charge and current is momentum of electrons or drift current through the windings w(in), w(out) and the inner coupling which A varies between capacitive (through dielectric air) and inductive (through the armature's metal containing flux F(w)) and there's a connection to CRT LOPTs which are permanently capacitive, and plasmas which are also capacitive/inductive.
Have a look at plasma balls, neon lights, etc that use 'starters' which are transformers or modern solid state inductors that drive the capacitance at a certain pole frequency (in-circuit resonance).
There is, therefore a standard transfer function H, with poles and zeros in both capacitive (charge movement or current I) and inductive terms (magnetic potential 'rotation' or flux through A the armature). A double whammy of a Hamiltonian with C and I terms and a complex pole-zero response, in t-t', or e^st for s, a complex frequency w/Laplacian H(0).Are you sure? This action cannot be undone. -
Member • Jun 7, 2009
another info:
The linear variable differential transformer (LVDT) is a type of electrical <a href="https://en.wikipedia.org/wiki/Transformer" target="_blank" rel="nofollow noopener noreferrer">Transformer - Wikipedia</a> used for measuring linear displacement. The transformer has three <a href="https://en.wikipedia.org/wiki/Solenoid" target="_blank" rel="nofollow noopener noreferrer">Solenoid</a> coils placed end-to-end around a tube. The centre coil is the primary, and the two outer coils are the secondaries. A cylindrical ferromagnetic core, attached to the object whose position is to be measured, slides along the axis of the tube.
An <a href="https://en.wikipedia.org/wiki/Alternating_current" target="_blank" rel="nofollow noopener noreferrer">Alternating current - Wikipedia</a> is driven through the primary, causing a <a href="https://en.wikipedia.org/wiki/Potential_difference" target="_blank" rel="nofollow noopener noreferrer">Potential Difference</a> to be induced in each secondary proportional to its mutual <a href="https://en.wikipedia.org/wiki/Inductance" target="_blank" rel="nofollow noopener noreferrer">Inductance</a> with the primary. The <a href="https://en.wikipedia.org/wiki/Frequency" target="_blank" rel="nofollow noopener noreferrer">Frequency</a> is usually in the range 1 to 10 <a href="https://en.wikipedia.org/wiki/Kilohertz" target="_blank" rel="nofollow noopener noreferrer">Kilohertz</a>.
As the core moves, these mutual inductances change, causing the voltages induced in the secondaries to change. The coils are connected in reverse series, so that the output voltage is the difference (hence "differential") between the two secondary voltages. When the core is in its central position, equidistant between the two secondaries, equal but opposite voltages are induced in these two coils, so the output voltage is zero.
When the core is displaced in one direction, the voltage in one coil increases as the other decreases, causing the output voltage to increase from zero to a maximum. This voltage is in <a href="https://en.wikipedia.org/wiki/Phase_(waves)" target="_blank" rel="nofollow noopener noreferrer">Phase (Waves)</a> with the primary voltage. When the core moves in the other direction, the output voltage also increases from zero to a maximum, but its phase is opposite to that of the primary. The magnitude of the output voltage is proportional to the distance moved by the core (up to its limit of travel), which is why the device is described as "linear". The phase of the voltage indicates the direction of the displacement.
Because the sliding core does not touch the inside of the tube, it can move without friction, making the LVDT a highly reliable device. The absence of any sliding or rotating contacts allows the LVDT to be completely sealed against the environment.
LVDTs are commonly used for position feedback in <a href="https://en.wikipedia.org/wiki/Servomechanism" target="_blank" rel="nofollow noopener noreferrer">Servomechanism</a>, and for automated measurement in machine tools and many other industrial and scientific applications.Are you sure? This action cannot be undone. -
Member • Jun 7, 2009
My First post here.and very nice to see all of you ppl.
and abt the post...
Nice explanation.
but has any one tried making one.
iam working on the LVDT reading system(display say..) to fit it on my machine for accurate measurement.
let me know if any one else working on it.
LVDT's are bit cheap.but the rest of the reading circuitry is costly.Are you sure? This action cannot be undone.