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Rotary variable differential transformer

A rotary variable differential transformer (RVDT) is an electromechanical designed to measure by converting rotary motion into a proportional (AC) electrical output signal through . The device operates on principles similar to its linear counterpart, the (LVDT), but is adapted for rotational measurement: it consists of a primary winding excited by an external voltage (typically 1-24 V RMS at 400 Hz to 20 kHz), two identical secondary windings connected in opposition, and a cam-shaped ferromagnetic attached to a rotating shaft. As the core rotates, it variably couples the between the primary and secondary coils, producing a differential output voltage that is zero at the null position and linearly proportional to the (typically within ±40 degrees, with sensitivity of 2-3 mV per degree). This contactless design ensures frictionless operation, high resolution, and infinite electrical resolution without mechanical wear. RVDTs are valued for their robustness, accuracy, and reliability in demanding environments, offering long lifespan, low cost, and resistance to variations in (-40°C to 85°C), (up to ), and (up to 50G). They find widespread applications in (e.g., controls, levers, and ), industrial (e.g., CNC machinery and process control), , military systems (e.g., ), and other precision positioning tasks like hydraulic actuators and engine fuel controls.

Fundamentals

Definition and Purpose

A rotary variable differential transformer (RVDT) is an electromechanical that converts angular mechanical input into a proportional (AC) electrical output voltage. This device operates on the principle of , where the angular position of a rotating modulates the between primary and secondary windings to produce an output signal linearly related to the displacement. RVDTs are typically designed to measure angular displacements within a range of up to ±80 degrees, providing high-resolution without physical contact between moving parts. The primary purpose of an RVDT is to enable precise, contactless sensing of angular position in applications demanding high reliability and durability, such as control systems in harsh environments. By delivering an analog output that directly corresponds to shaft rotation, RVDTs facilitate accurate monitoring and in scenarios like flight surfaces, industrial automation, and mechanisms, where they withstand extreme temperatures, vibrations, and corrosive conditions while maintaining infinite resolution and long operational life. Their non-contacting, brushless design minimizes wear, ensuring repeatable performance over millions of cycles in closed-loop systems. RVDTs were developed in the mid-20th century as a rotary adaptation of transformer-based sensors, evolving from (LVDT) technology around the 1940s for industrial and military applications. This evolution addressed the need for reliable angular measurement in rotating mechanisms, building on wartime advancements in electromechanical sensing to support precision control in emerging and sectors.

Relation to Linear Variants

The rotary variable differential transformer (RVDT) is structurally adapted from the (LVDT) to accommodate angular motion rather than linear displacement. In an RVDT, a cam-shaped ferromagnetic rotates within a fixed assembly containing primary and secondary windings, enabling measurement of rotational angles. In contrast, the LVDT employs a linearly sliding ferromagnetic along a non-magnetic tube, positioned between stationary coils to detect straight-line movement. This rotational design in the RVDT introduces symmetry around the axis, allowing for bidirectional angular sensing without the end-stop limitations typical of linear setups. Both devices operate on the same differential transformer principle, where an excitation voltage applied to the primary winding induces voltages in two secondary windings, with the net output varying proportionally to the core's position relative to a null point. However, the RVDT's output represents , typically in degrees over ranges such as ±40° or up to ±80° in some configurations, whereas the LVDT quantifies linear in millimeters, often spanning ±100 μm to ±25 cm. This adaptation maintains the contactless, high-resolution nature of the technology while tailoring it for rotary applications like shaft position feedback. Shared operational prerequisites include the need for stable excitation—commonly at frequencies from 400 Hz to 20 kHz—and a null position where secondary voltages balance to zero output, providing a for . The RVDT's handling of ensures consistent performance across the angular range, distinguishing it from the unidirectional linearity of the LVDT while preserving electromagnetic coupling efficiency.

Construction

Core Components

The core components of a rotary variable differential transformer (RVDT) are the primary , secondary s, ferromagnetic core, and stator housing, which together enable the of into an electrical signal. The primary functions as the single winding, receiving an voltage to establish an alternating that couples with the secondary s. It is typically supplied with voltages of 3 to 15 V and frequencies ranging from 400 Hz to 20 kHz, allowing for optimized performance in various applications. The secondary coils comprise two identical windings arranged symmetrically and connected differentially, such that their outputs are subtracted to yield a signal proportional to the core's angular position relative to the . Positioned on the stationary , these coils detect flux variations induced by the rotating core, with typical sensitivities of 2 to 3 mV/V per over ranges up to ±40°. The ferromagnetic is the rotating element affixed to the , serving to direct and modulate linkage between the primary and secondary coils based on its angular orientation. Constructed from high-permeability nickel-iron alloys for efficient flux conduction, it often adopts cam-shaped or cylindrical geometries to achieve in output response across the measurement range. The housing encases the assembly in a non-magnetic structure, supporting the windings and providing bearings for low-friction shaft rotation. Commonly made of anodized aluminum to minimize losses and , it ensures precise alignment and environmental protection for the internal components.

Materials and Assembly

The core of a rotary variable differential transformer (RVDT) is typically constructed from high-permeability ferromagnetic materials, such as iron-nickel alloys, to minimize losses and optimize linkage. The windings, consisting of a primary excitation coil and two secondary output coils, are made from insulated wire to facilitate efficient . ball bearings, such as ABEC 3 types, support the rotating shaft for low-friction operation and long-term durability. The housing is usually fabricated from anodized aluminum or passivated to provide mechanical protection while maintaining non-magnetic properties that prevent interference with the internal . Material selection emphasizes environmental robustness, with components rated for operating temperatures from -55°C to +150°C to accommodate and industrial demands. Vibration tolerance extends to 20 g over 2 kHz, ensuring stability under dynamic conditions, while resistance reaches 30 g for 11 ms half-sine pulses. These properties collectively enable reliable performance in harsh settings without compromising sensor accuracy. In the assembly process, the primary and secondary coils are wound onto a and integrated into the structure. The ferromagnetic core is affixed to a or compatible and supported by precision bearings to allow smooth rotation. The complete rotor- assembly is then inserted into the cylindrical , sealed against moisture and contaminants, and fitted with shaft extensions for mechanical coupling to the application. Lead wires, typically AWG 28 with PTFE insulation, are connected to the coils for external interfacing. This modular construction facilitates customization for specific angular ranges and environmental requirements.

Operation

Electromagnetic Principle

The electromagnetic principle of the rotary variable differential transformer (RVDT) is based on the of between a primary and two secondary s, modulated by the of a ferromagnetic . An (AC) excitation voltage, typically in the range of 1 to 10 at frequencies from 400 Hz to 20 kHz, is applied to the primary mounted on the . This generates an oscillating within the core, which links differentially to the two secondary s also wound on the . Rotation of , attached to the input shaft, alters the path and thus the to each secondary . One secondary experiences increased while the other sees decreased , inducing voltages of equal but opposite relative to the . The output voltage, obtained by subtracting the secondary signals, reflects the from the reference position. At the null position, corresponding to zero (often aligned with the core's neutral orientation), the to both secondaries is equal, producing identical induced voltages that cancel out, resulting in zero differential output (V_out = 0). For small displacements θ, the output voltage is proportional to the sine of the angle (sin θ), approximating a linear relationship since sin θ ≈ θ in radians. Specialized core geometries, such as cam-shaped designs, extend this near-linear response to a typical range of ±40°, minimizing for precise .

Signal Output and Processing

The output signal of a rotary variable differential transformer (RVDT) is derived from the difference in voltages induced in its two secondary windings, denoted as V_{\text{sec1}} and V_{\text{sec2}}. The output voltage is given by V_{\text{out}} = |V_{\text{sec1}} - V_{\text{sec2}}|, where the magnitude represents the amplitude proportional to the \theta, and the phase shift between the secondary signals indicates the direction of relative to the null position. This configuration ensures that at \theta = 0^\circ (null position), the secondary voltages are equal and opposite, resulting in V_{\text{out}} = 0. For small s within the linear range (typically ±40°), the output approximates a linear relationship V_{\text{out}} = G \theta, where G is the , often expressed in mV/ or mV/V/ depending on the voltage. The RVDT employs , where the carrier signal—typically an AC excitation at 400 Hz to 20 kHz—remains constant in frequency and , while the envelope of the output signal varies directly with [\theta](/page/Theta). This modulation arises from the varying between the primary and secondary windings as the turns, producing an AC output whose scales linearly with displacement but includes a 180° phase reversal across the point to denote direction. The condition at \theta = 0 eliminates any output, providing a point for bidirectional . To interface the AC output with digital systems or controllers, signal processing is essential, beginning with demodulation using phase-sensitive detectors (PSDs) or synchronous rectifiers to extract the and convert it to a DC voltage proportional to \theta. These detectors, often implemented in integrated circuits like the AD698, compare the output phase against the excitation reference to preserve directional information and reject components. Subsequent low-pass filtering removes high-frequency and carrier remnants, while amplification scales the DC signal for compatibility with analog-to-digital converters (ADCs) or control loops, ensuring accurate position feedback with minimal distortion.

Types

Standard Configurations

The standard configuration of a Rotary Variable Differential Transformer (RVDT) employs a single-core design featuring a housed assembly with a rotating ferromagnetic attached to the input . This setup provides a basic, non-contacting electromechanical that converts into an electrical signal through electromagnetic coupling, offering infinite resolution and frictionless operation for reliable, repeatable position sensing. Standard RVDTs typically support angular measurement ranges of ±20° to ±60° relative to the null position, with linearity maintained over the full range to ensure precise output proportionality to shaft rotation. Compact models, such as those with a 1-inch (25 mm) diameter housing, achieve accuracies of 0.5° or better, making them suitable for space-constrained applications, while larger variants (e.g., up to 1.5 inches or 38 mm in diameter) offer increased torque resistance for more demanding mechanical environments. Excitation in standard configurations uses AC voltage at frequencies of 3-5 kHz, with input levels typically between 3 and 8 V , resulting in output linearity better than 0.5% of full scale for most operational ranges. This excitation standard facilitates compatibility with common electronics and supports the core's operation by inducing a variable differential voltage in the secondary windings as the rotor turns.

Specialized Variants

Specialized variants of rotary variable differential transformers (RVDTs) incorporate modifications to address specific environmental or performance demands, extending their utility beyond standard configurations. These adaptations maintain the core electromagnetic principles while enhancing , , or measurement range. High-temperature variants are engineered to function reliably in demanding thermal conditions, with operating ranges typically spanning -67°C to +180°C. Such designs employ robust to minimize to temperature fluctuations, ensuring consistent measurement in harsh environments like those encountered in systems. Dual-channel or redundant designs integrate multiple independent RVDT channels—often two or three—within a single housing to provide and enhanced reliability. This configuration allows continuous operation even if one channel fails, making it ideal for safety-critical systems where is paramount; for instance, channels are electrically segregated but share a common mechanical . Other specialized variants include DC-output RVDTs, which incorporate built-in to provide voltage or current outputs proportional to angular position, simplifying integration with modern control systems. Additionally, Rotary Variable Inductance Transformers (RVITs) are inductive variants that operate without a primary winding, using a varying core for position sensing in limited angular ranges. Related technologies, such as brushless resolvers, utilize multi-pole windings on the and to achieve absolute angular positioning over a full 360° , producing output signals proportional to the for precise determination through . These differ from conventional RVDTs in winding and but share principles.

Applications

Aerospace and Defense

In aerospace applications, rotary variable differential transformers (RVDTs) serve as critical sensors in flight systems, providing precise angular position data for actuators in controls and control surfaces such as ailerons and rudders. These sensors enable monitoring and adjustment of control surface positions, ensuring stable and responsive aircraft maneuvering under varying flight conditions. For instance, in commercial and , RVDTs integrate with systems to deliver non-contact, high-resolution measurements that support pilot inputs and automated stability augmentation. In defense systems, RVDTs are employed for , where they function as angular sensors in gimbal-mounted assemblies to track and adjust the orientation of or fins in . This capability allows for accurate trajectory corrections during flight, enhancing hit probability in dynamic environments. Military-grade RVDTs, often designed to withstand high vibrations and , provide reliable in guidance electronics.

Industrial and Automotive

In industrial automation, rotary variable differential transformers (RVDTs) serve as critical position feedback devices in robotic arms and computer numerical control (CNC) machines, enabling precise angular control during operations. These sensors provide real-time data on joint orientation and tool positioning, allowing systems to adjust movements dynamically for tasks such as , , and component insertion, which enhances efficiency and reduces errors in high-volume environments. For instance, in robotic arms, RVDTs measure angular displacements up to ±60 degrees with high , ensuring accurate path following without mechanical wear from contact-based alternatives. In the automotive sector, RVDTs are integrated into engine management and stability systems for valve and steering angle sensing, where they deliver reliable angular position signals to optimize performance and safety. position sensing uses RVDTs to monitor valve rotation, providing for units to regulate delivery and , which supports smooth and emissions in modern engines. Similarly, in steering systems, these sensors track wheel angles to assist in features like , offering non-contact measurement resilient to vibrations and variations common in underhood environments. For metal forming and verification processes, RVDTs facilitate in-process monitoring of press angles and dimensional checks in heavy machinery, ensuring during operations like stamping and bending. By detecting angular deviations in real time, they enable adjustments to maintain tolerances, preventing defects in formed parts and supporting automated verification of product dimensions against specifications. This application is particularly valuable in high-precision presses, where RVDTs' robustness allows integration into environments with significant mechanical stress and .

Performance

Advantages

Rotary variable differential transformers (RVDTs) exhibit high reliability due to their brushless, non-contacting inductive design, which provides infinite without mechanical wear from . This frictionless operation enables a long lifespan exceeding 100 million cycles, ensuring consistent and repeatable over extended use. RVDTs demonstrate strong environmental robustness, with low sensitivity to temperature variations characterized by a of ±0.05%/°C maximum. They maintain accuracy despite exposure to high , , and excitation voltage fluctuations up to 7.5%, making them suitable for demanding conditions without degradation. In terms of cost-effectiveness, RVDTs feature simple construction with minimal , contributing to reduced and expenses. Their compact , achievable in diameters as small as 19 mm (size 8 housing), facilitates integration into space-constrained systems, while offering excellent linearity with errors typically between 0.1% and 0.5% of .

Limitations and Considerations

Rotary variable differential transformers (RVDTs) are constrained by a limited angular measurement range, with a maximum linear range of up to ±80° for specialized models, though typical ranges are ±20° to ±40°, which makes them unsuitable for applications requiring full 360° rotation without additional mechanical gearing to extend the effective range. This restriction arises from the device's electromagnetic design, where the core's displacement relative to the coils produces optimal only over a narrow , beyond which output nonlinearity and reduced resolution degrade performance. RVDTs exhibit sensitivity to external , necessitating shielding to prevent that could induce erroneous outputs and compromise accuracy. As differential devices, they are not inherently absolute position sensors but instead rely on a null reference position where secondary outputs balance, providing relative displacement measurements that require an initial reference establishment for reliable operation. In environments with stray electromagnetic noise, such as near motors or power lines, additional magnetic shielding—often using enclosures—is essential to maintain . Due to potential wear on shaft bearings over time and environmental factors like temperature variations, RVDTs demand periodic calibration to verify linearity and mitigate output drift. Calibration involves exciting the device at its nominal frequency and voltage while adjusting to the null position, followed by checks across the full range using known angular standards to correct for any deviations caused by material fatigue or thermal expansion effects. In high-cycle applications, such as aerospace controls, periodic recalibration may be required to ensure long-term precision.

References

  1. [1]
    LVDT/RVDT Tutorial and Reference - Aerospace DAQ, Test, HIL - UEI
    It measures absolute linear displacement. RVDT is a Rotary Variable Differential Transformer. It measures absolute rotary angle.
  2. [2]
    RVDT Sensors (Rotary Variable Differential Transformers)
    A Rotary Variable Differential Transformer (RVDT) is a sensor used to measure angular displacement. It operates by converting rotary motion into a corresponding ...Common Applications Of Rvdts · Modern Alternative To Rvdts · Rvtd Sensors Faqs
  3. [3]
    RVDT – Rotary Variable Differential Transformer Explained
    The main function of RVDT is to detect the angular displacement and converts it into an electrical signal. The both the RVDT and LVDT workings are similar, but ...<|control11|><|separator|>
  4. [4]
    RVDT(Rotary Variable Differential Transformer) Basics - Utmel
    Feb 2, 2021 · A Rotary Variable Differential Transformer (RVDT) is an electromechanical transducer that provides a variable alternating current (AC) output ...
  5. [5]
    [PDF] Rotary Variable Differential Transformer (RVDT)
    A Rotary Variable Differential Transformer (RVDT) is an electromechanical transducer that provides a variable alternating current (AC) output voltage that is ...Missing: invention history
  6. [6]
    RVDTs | Sensata Technologies
    The lightweight, robust sensors are capable of up to ±80°angular range in single or multiple channel designs. RVDTs with integral miniaturized anti-backlash ...
  7. [7]
    [PDF] Ask the Engineer | G.W. Lisk
    Oct 26, 2021 · Rotary Variable Differential Transformers (RVDTs) are electromechanical transducers that provide measurement of angular displacement and offer ...
  8. [8]
    THE LVDT AND RVDT - ResearchGate
    This chapter presents the history of the linear variable differential transformer (LVDT) and rotary variable differential transformer (RVDT) position sensors.
  9. [9]
    What Is The Difference Between A LVDT and RVDT? - Sentech Inc
    Mar 8, 2023 · LVDTs are typically used for linear position sensing, while RVDTs are used for angular position sensing. LVDTs are typically less expensive and more accurate ...Missing: definition | Show results with:definition
  10. [10]
    Difference between Linear Variable and Rotary Variable Differential ...
    Sep 22, 2022 · LVDT and RVDT are types of passive transducers used for the measurement of linear and angular displacements, respectively.
  11. [11]
    [PDF] SECTION 6 POSITION AND MOTION SENSORS - Analog Devices
    The core moves linearly inside a transformer consisting of a center primary coil and two outer secondary coils ... rotary variable differential transformer ...
  12. [12]
    Introduction to Rotational Variable Differential Transformer (RVDT)
    Whereas the LVDT uses a cylindrical iron core, the RVDT uses a rotary ferromagnetic core. A schematic is shown below.Missing: material | Show results with:material
  13. [13]
    Linear Variable Differential Transformer - ScienceDirect.com
    As shown in Figure 4.6, rotating a ferromagnetic-core bearing that is supported within a housed stator assembly is the basis of RVDT construction and operation.
  14. [14]
    [PDF] Electrical Specifications Environmental Specifications Materials ...
    Core: Hi-permeability nickel-iron alloy. Magnet Wire: Film insulated copper ... The NewTek RV series is a family of RVDT rotary position sensors for industrial ...
  15. [15]
    AC Operated / Light Weight RVDT - TE Connectivity
    Case Material Anodized Aluminum ... Bearing Type ABEC 3 Precision Ball Bearing. Related Materials. Datasheets & Catalog Pages. AC Operated, Light Weight RVDT pdf ...
  16. [16]
    R30D RVDT - Althen Sensors
    RVDT sensors; R30D RVDT. R30D rotary variable differential transformer. R30D ... Housing material, Aluminium, anodized. Input current, 25mA maximum. Input ...
  17. [17]
    Rotary Variable Differential transformer (RVDT) sensor cluster with ...
    Armature 116a and 116b is made up of solid-state magnetic material (for example, iron-nickel alloy), and it can have permeability higher, and can be soldered or ...<|separator|>
  18. [18]
    None
    ### Materials
  19. [19]
    RV Series RVDT | Angular Position Sensor
    Excellent Linearity ±0.5% of Full Range. Shock and vibration tolerant. Wide operating temperature range (-65°F to 221°F). Contactless RVDT Technology ...
  20. [20]
    [PDF] 4.3 ROTARY VARIABLE DIFFERENTIAL TRANSFORMER (RVDT)
    The purpose of a Rotary Variable Differential Transformer (RVDT) is to measure rotational angles, and its principle of operation is same as that of an LVDT.Missing: definition history
  21. [21]
    [PDF] Duplex RVDT Size 08
    The RVDT operation is based on electromagnetism and variable reluctance technology, so that no brushes are needed. Thus, RVDT are simple and robust sensors ...
  22. [22]
    Single-Channel RVDT Sensors - Sensata Technologies
    A Rotary Variable Differential Transformer (RVDT) is an angular position sensor that produces an output voltage proportional to the angular displacement of a ...
  23. [23]
    [PDF] CHAPTER 3: SENSORS - Analog Devices
    The shaft is equivalent to the core in an LVDT, and the transformer windings are wound on the stationary part of the assembly. However, the RVDT is linear over ...
  24. [24]
    Linear Variable Differential Transformers - Analog Devices
    A look at the linear variable differential transformer (LVDT) for measuring linear distance in modern machine-tools, robotics, avionics, and manufacturing.
  25. [25]
    Application of AD698 in RVDT sensor measurement - EEWORLD
    May 29, 2012 · The VEXC output drives the RVDT/LVDT primary coil and uses two synchronous demodulation stages to decode the primary and secondary voltages.
  26. [26]
    US4591795A - Signal conditioning circuit for L/R VDT sensors
    A highly accurate signal conditioning circuit for use with a linear/rotary variable differential transformer (L/R VDT) operating in a unipolar mode is ...
  27. [27]
    AC RVDT for Harsh Environments | TE Connectivity
    The R36AS RVDT (Rotary Variable Differential Transformer) is an angular position sensor that incorporates a proprietary non-contact design.
  28. [28]
    rotary variable differential transformer (rvdt) - sensors division
    Temperature range -67°C to +180°C; > 200,000 MTBF (with gearhead). APPLICATIONS: High lift flight controls system position and asymmetry sensing; Environmental ...
  29. [29]
    Multi-Channel RVDT Sensors - Sensata Technologies
    Multi-channel RVDTs are the sensor of choice. This is often the case for military fly-by-wire aircraft. Up to three separate channels can be placed in tandem ...
  30. [30]
    [PDF] Rotasyn vs. Resolver vs. RVDT | Admotec
    Resolver vs. RVDT. All 3 angular brushless sensors are rotating differential transformers with a precise E.Z. (Electrical zero). Angular. Sensor. Signal. Input.<|control11|><|separator|>
  31. [31]
    Brushless Resolvers - Computer Conversions Corporation
    Computer Conversions GT and HB transducers are brushless, Electromagnetic, Rotary Sensors used to provide Precise Absolute or Incremental Position, ...
  32. [32]
    How LVDTs and RVDTs Help Commercial Planes Fly - Sentech Inc
    Dec 21, 2020 · The LVDT works at a voltage input of between 1-24 Volts RMS, and the RVDT operates at an input voltage of up to 3 Volts RMS. The LVDT has a ...
  33. [33]
    Rotary Variable Differential Transformers (RVDTs) - Moog Inc.
    A Rotary Variable Differential Transformer (RVDT) is an electromechanical transducer that provides a variable alternating current (AC) output voltage.Missing: components | Show results with:components
  34. [34]
    Different Types Of RVDT Applications - Sentech Inc
    Mar 21, 2023 · Aerospace Industry. RVDTs are commonly used in the aerospace industry for measuring the position and motion of aircraft engines, landing gears, ...
  35. [35]
    [PDF] aerospace & defense - Automation | Honeywell
    Honeywell precision potentiometers deliver real-time information to a missile guidance system while the missile is en route, providing reliable directional ...
  36. [36]
    RVDTs - Sensata Technologies
    RVDTs are the industry standard for angular and rotary measurements in space, aerospace & industrial applications. The lightweight, robust sensors are capable ...
  37. [37]
    NewTek Rotary Position Sensors Ensure Accurate Sensing in ...
    Aug 24, 2021 · Rotary position sensors provide highly accurate angular displacement measurements to ensure the correct positioning of robotic arms. With a ...
  38. [38]
    LVDT Sensor Selector | Position Sensors and Signal Conditioners
    Extremely reliable with greater than 100 million cycles; Measurement ranges ... AC RVDT Rotary Position Sensor. RV Series. Size 8 and Size 11; Available in ...
  39. [39]
    [PDF] | RVDT SENSORS - Sensata Technologies
    | RVDT SENSORS. Description. Features. • High reliability (MTBF of 1,000,000 ... The lightweight, robust sensors are capable of up to ±80°angular range in single ...
  40. [40]
    LVDT: Advantages and Disadvantages | Test & Measurement World
    Advantages of LVDT · Wide Measurement Range: LVDTs can accurately measure displacements ranging from 1.25 mm all the way up to 250 mm. · Frictionless Operation: ...Missing: reliability | Show results with:reliability
  41. [41]
    Study of Magnetic Interference on an LVDT: FEM Modeling and ...
    Static or slowly varying magnetic fields can affect the performances of linear variable differential transformer by inducing a position reading drift.Missing: RVDT | Show results with:RVDT
  42. [42]
    [PDF] Rotary Variable Differential Transformer(RVDT)
    Disadvantages. • Screw type core- Chance for friction and leads to wear and tear. • Only detected the angles in between -40 and +.
  43. [43]
    Calibration technique for sensitivity variation in RVDT type ...
    Aug 7, 2025 · This paper presents a calibration technique for RVDT sensitivity variation, which occurs as a result of using high excitation frequency and ...