Fixed Inductors
Fixed Inductors are passive components used in electronic circuits to store magnetic energy and limit current changes. Their inductance is preset during manufacturing and cannot be adjusted.
1. What are Fixed Inductors?
1) Basic Definition
Fixed Inductors consist of a coil wound with a wire and a magnetic core. They store electrical energy through self-inductance and hinder current mutations through magnetic field changes. Their inductance value (in Henry/H) is fixed at the factory and cannot be adjusted manually.
2) Core Parameters
Inductance: The nominal value range is wide (such as 0.1μH to 22000μH), which needs to be selected according to circuit requirements;
Rated Current: Determines the maximum DC operating current that the inductor can withstand (typical values are 0.05A to 1.6A);
Error Range: Commonly ±5% to ±10%, and the precision model has a lower error;
Packaging Form: Divided into sealed (vertical/horizontal) and non-sealed to meet the installation needs of different scenarios.
2. What is the Structure and Manufacturing Process of Fixed Inductors?
1) Components
Coil: Wound by enameled copper wire or alloy wire, with shapes including spiral, ring, etc.;
Core: Commonly used ferrite materials to improve inductance efficiency and reduce volume;
Packaging Material: Epoxy resin or plastic shell to ensure mechanical strength and environmental isolation.
2) Packaging Technology
Adopting miniaturized design (such as the Murata LQP03HQ2N2B02D model), some models have a unit weight of only 0.02mg, suitable for high-frequency circuit integration.
3. Classification and Typical Applications of Fixed Inductors
1) Classification Method
By Function: including filter inductors, energy storage inductors, electromagnetic interference (EMI) suppression inductors, etc.;
By Packaging: vertical (such as TDK color code inductors), horizontal (such as LG1/LGA series), etc.
2) Typical Application Scenarios
Power Supply Circuit: filter out high-frequency noise and stabilize output voltage (such as DC-DC converter);
Communication Equipment: used for radio frequency (RF) signal matching and tuning (such as Murata LQP series);
Industrial Control: used as a sensor element to detect changes in physical quantities (such as position and speed).
4. Industry Standards and Quality Control of Fixed Inductors
International Specifications
The IEC 60938-1:2021 standard defines the general test requirements for inductors for EMI suppression, covering material testing, AC withstand voltage testing, etc., to ensure product reliability.
Quality Certification
Mainstream brands (such as Murata and TDK) have passed RoHS certification and meet environmental and safety requirements.
5. Selection Recommendations for Fixed Inductors
The inductance, rated current, volume limit, and operating frequency range should be considered comprehensively during design. Low-loss cores and miniaturized packaging models are preferred for high-frequency scenarios.