Many people easily confuse shielded inductors with unshielded inductors. The two different names arise from the different magnetic shielding properties. Shielded inductors include surface mount inductors and I-beam inductors, and the same applies to unshielded inductors.
Many people easily confuse shielded inductors with unshielded inductors. The two different names arise from the different magnetic shielding properties. Shielded inductors include surface mount inductors and I-beam inductors, and the same applies to unshielded inductors.
So how can we quickly distinguish between shielded and unshielded inductors? What are the differences between them? We will discuss this from three aspects below.
Distinguish by appearance
Shielded inductors have an external magnetic shielding structure, so the coil windings that can be seen from the outside are definitely unshielded inductors, while the coil windings of shielded inductors cannot be seen from the outside.
However, there is one exception to note: an inductor whose coil is not visible is not necessarily a shielded inductor; it could also be an I-shaped inductor with a heat-expanding sleeve.
Distinguishing by magnetic circuit composition structure
1. The magnetic circuit structure of a shielded inductor is a closed magnetic circuit structure: The closed magnetic circuit structure is composed of magnetic materials and has very low magnetic impedance. The representative magnetic core is a toroidal core, which is a closed magnetic circuit structure.
2. Unshielded inductor magnetic circuit structure is an open magnetic circuit structure: Since the magnetic circuit components are exposed, there is a very obvious air gap, and its impedance is relatively large. The representative magnetic cores are U-shaped and EE-shaped magnetic cores.
Performance differentiation
1. Due to the different magnetic shielding structures of shielded and unshielded inductors, shielded inductors are larger in volume than unshielded inductors for the same inductance and operating current.
2. Unshielded inductors are characterized by high saturation, small size, and low impedance. They are mainly found in through-hole inductors, some surface-mount inductors (GCD series, which are quickly being replaced by shielded inductors), and rod-shaped inductors.
3. Shielded inductors are characterized by high power, low resistance, and high current. They are mainly used in circuits with high EMC requirements, involving signal transmission, intelligent computing, etc., such as mobile phones, computers, high-quality audio equipment, etc.
