INDUCTANCE for Dummies

Inductance is an important concept in the field of electromagnetism and electrical circuits. It refers to the property of an electrical conductor or coil to oppose changes in current flow. It is denoted by the symbol "L" and is measured in Henrys (H).

Inductance arises from the phenomenon of electromagnetic induction, discovered by Michael Faraday. When the current flowing through a conductor changes, it induces a voltage in nearby conductors or coils. This voltage, in turn, creates an opposing electromagnetic force that resists the change in current.

The key component that exhibits inductance is an inductor. An inductor is typically made of a coiled wire wound around a core, which can be composed of various materials such as iron, ferrite, or air. The number of turns in the coil and the physical properties of the core material determine the inductance value.

The inductance of an inductor depends on several factors, including the number of turns in the coil, the cross-sectional area of the coil, the length of the coil, and the permeability of the core material. The inductance value determines how much opposition an inductor presents to changes in current.

Inductance has several important applications in electrical circuits. One of the primary applications is in the construction of transformers. Transformers utilize inductance to transfer electrical energy between different voltage levels efficiently.

Inductors are also used in various electronic devices and circuits for purposes such as filtering out unwanted frequencies, storing energy, and providing impedance matching. They play a crucial role in smoothing out alternating current (AC) signals and suppressing electrical noise.

The most common device used to measure inductance is called an inductance meter or an LCR meter (LCR stands for inductance, capacitance, and resistance). An LCR meter is a specialized instrument that can measure the inductance of an inductor accurately.

LCR meters typically work by applying an AC voltage or current to the inductor and measuring the resulting AC response. They can measure the phase shift between the applied voltage or current and the resulting current or voltage across the inductor. From this phase shift and the known values of the applied signal, the LCR meter can calculate the inductance value.

Another method to measure inductance involves using an LC tank circuit. A known capacitor and the inductor under test are connected in parallel to form an LC tank circuit. By measuring the resonant frequency of this circuit, the inductance can be calculated using the known capacitance value.

For more precise and accurate measurements, specialized techniques like the Maxwell-Wien bridge or the Anderson bridge can be employed. These bridge circuits utilize the principles of impedance matching and null detection to determine the inductance value accurately.

It's worth noting that the measurement of inductance can be affected by factors such as stray capacitance and resistance in the circuit. To obtain accurate results, it's essential to consider these factors and minimize their influence during the measurement process.

Overall, inductance can be measured using various methods and instruments, depending on the accuracy required and the available equipment. LCR meters are commonly used for general inductance measurements, while more specialized techniques are employed for specific applications or high-precision measurements.