Hall Effect - Copy.pptx process and instrumentation
- 2. What is Hall Effect TRANSDUCER? Definition: The hall effect element is a type of transducer used for measuring the magnetic field by converting it into an emf. The direct measurement of the magnetic field is not possible. Thus the Hall Effect Transducer is used. The transducer converts the magnetic field into an electric quantity which is easily measured by the analogue and digital meters.
- 3. Contruction ; COMPONENTS OVERVIEW Hall Element Magnet Current Source Voltage Sensor Amplifier
- 4. HALL ELEMENT Material: Usually a thin strip of semiconductor material. Function: Generates a small voltage proportional to the magnetic field.
- 5. MAGNET Type: Permanent magnet or electromagnet. Purpose: Provides a consistent and known magnetic field.
- 6. CURRENT SOURCE Function: Supplies a steady current through the Hall element. Importance: Ensures a consistent Hall voltage output.
- 7. VOLTAGE SENSOR Role : Detects and measures the small Hall voltage generated by the Hall element. Sensitivity: Crucial for accurate detection of the magnetic field.
- 8. Amplifier Function: Amplifies the small Hall voltage to a readable level.- Type: Operational amplifier (Op-Amp) is commonly used.
- 9. DIAGRAM
- 10. Operation The principle of hall effect transducer is that if the current carrying strip of the conductor is placed in a transverse magnetic field, then the EMF develops on the edge of the conductor. The magnitude of the develop voltage depends on the density of flux, and this property of a conductor is called the Hall effect. The Hall effect element is mainly used for magnetic measurement and for sensing the current. The metal and the semiconductor has the property of hall effect which depends on the densities and the mobility of the electrons. Consider the hall effect element shown in the figure below. The current supply through the lead 1 and 2 and the output is obtained from the strip 3 and 4. The lead 3 and 4 are at same potential when no field is applied across the strip. When the magnetic field is applied to the strip, the output voltage develops across the output leads 3 and 4. The develops voltage is directly proportional to the strength of the material. The output voltage is Where The I is the current in ampere and the B is the flux densities in Wb/m2 The current and magnetic field strength both can be measured with the help of the output voltages. The hall effect EMF is very small in conductors because of which it is difficult to measure. But semiconductors like germanium produces large EMF which is easily measured by the moving coil instrument.
- 12. Characteristics Sensitivity to Magnetic Fields: Measures magnetic field strength by generating a Hall voltage. The output voltage is directly proportional to the magnetic field strength. Current Dependency: The Hall voltage depends on the current passing through the transducer. Higher currents produce higher Hall voltages for the same magnetic field. Material Dependency: Different materials used in the transducer have different sensitivities. The material's carrier concentration and mobility affect the Hall voltage. Directional Sensitivity: The transducer is sensitive to the direction of the magnetic field. Reversing the direction of the magnetic field will reverse the polarity of the Hall voltage. Linear Response: In many materials, the Hall voltage has a linear relationship with the magnetic field and current. This makes calibration and measurement straightforward. Temperature Sensitivity: The Hall coefficient, which determines sensitivity, can vary with temperature. Compensation may be needed for accurate measurements in varying temperatures. Non-invasive Measurement: Hall effect transducers can measure magnetic fields without direct contact. Useful for applications where physical contact is impractical or undesirable. Robust and Durable: These transducers are often durable and can operate in harsh environments. Suitable for industrial applications. Wide Application Range: Used in current sensing, speed detection, position sensing, and magnetic field measurement. Common in automotive, industrial, and consumer electronics. Compact and Lightweight: Hall effect transducers are typically small and lightweight. Ideal for applications with space constraints.
- 14. ADVANTAGES No Contact Needed: Hall effect transducers measure magnetic fields without touching the object. This is good for places where you can't reach or where contact is not possible. Strong and Durable: They work well in tough conditions, making them perfect for industrial use. Many Uses: They are used for measuring current, speed, position, and magnetic fields in cars, factories, and electronics. Small and Light: These transducers fit in small spaces and are easy to handle. Very Sensitive: They can detect very small changes in magnetic fields, making them very accurate. Easy to Read: They give a straight-line (linear) output, making it simple to understand measurements. Works with Fast Changes: Hall effect transducers can measure quick changes in magnetic fields, which is useful for dynamic situations. Long-Lasting: They have no moving parts, so they last a long time and need little maintenance. Stable in Different Temperatures: They work accurately even when temperatures change. Low Power Use: They use little electricity, which is good for battery-powered devices. Affordable: Hall effect transducers are cheaper than many other types of sensors, making them a cost-effective choice. Easy to Add to Systems: They are simple to connect to other electronic devices and systems.
- 15. DISADVANTAGES Sensitive to Temperature Changes: Hall effect transducers can be affected by temperature changes, which might require adjustments to keep measurements accurate. Limited to Measuring Magnetic Fields: They can only measure magnetic fields and not other types of forces or parameters.. Sensitivity to Alignment: They need to be properly aligned with the magnetic field for accurate readings. Misalignment can lead to errors. Limited Range: The range of magnetic field strength they can measure is limited. Very strong or very weak fields might not be measured accurately. Noise Interference: They can be affected by electrical noise, which can interfere with their accuracy. Sensitivity to External Magnetic Fields: Nearby magnetic fields can affect their readings, which can be a problem in environments with lots of magnetic interference. Low Output Voltage: The Hall voltage generated is usually small and might need amplification to be useful, which adds to the complexity of the system. Dependent on Material Quality: The quality of the material used in the transducer affects its performance. Poor quality materials can lead to inaccurate measurements. Temperature Drift: The output can drift with temperature changes over time, requiring frequent recalibration. Higher Initial Cost: While they are affordable compared to some sensors, high-quality Hall effect transducers can still be expensive initially. Power Supply Required: They need a constant power supply to work, which can be a drawback for certain applications.
- 16. Hall effect sensor applications Hall effect sensors are used for picking up on the voltage induced on a conductor by a magnetic field. This sensor output can be proportional to the magnetic field intensity and direction, or it can be binary, based on electronics embedded in the sensing package.
- 17. Door open-closed sensor Perhaps the most common use for Hall effect sensors in everyday life and smart spaces is the door (or window) open/shut sensor. A magnet is placed on a door frame while the sensor unit is placed on the door. When shut, the door sensor aligns with the magnet and triggers the Hall effect sensor. The Hall effect sensor then turns off when the door is ajar. This theme has many variations that can be integrated into an alarm system or other smart space accommodations.
- 18. Brushless DC (BLDC) motor control Hall effect sensors are essential for controlling certain types of BLDC motors, allowing for precise speed control based on the magnetic effects of the moving rotor. Other BLDC motor configurations use back-EMF for control.
- 19. Bicycle speed detection Bicycle computers typically feature a permanent magnet affixed to a spoke, which passes by a sensor unit once every revolution. This magnetic cycling is equivalent to the wheel’s RPM, which can intuit a bicycle’s linear speed via the wheel diameter and a bit of math. A Hall effect sensor is used for detecting the magnet’s presence, passing data to other bike computer electronics.
- 20. Industrial Hall effect sensor:
- 22. Current sensing Just as a Hall effect sensor can pick up magnetic fields from permanent magnets, these devices can also sense magnetic fields generated by the flow of electrical current. In this configuration, a Hall effect device acts as a non-contact current sensor, allowing for monitoring without the need to modify a wiring setup. A Hall effect sensor can be put around an electric line, so you don’t have to deal with connections/disconnections directly.
- 23. Hall effect sensor automotive applications Vehicles have an exceptional number of moving parts, and Hall effect sensors can be implemented to monitor internal operations. With better sensing, efficiency can be improved in traditional gas-powered automobiles and emerging electric vehicles.
- 24. Current sensing