Do You Know How To Measure The Inductance Of The Patch?


For the patch inductors, it is known that its application is relatively wide, the English name is Chip inductors, also known as power inductors, high current inductors and surface mounted high power inductors. It has the characteristics of miniaturization, high quality, high energy storage and low resistance. Because the patch inductance is usually composed of coil and magnetic core, usually are closed, so how do I measure the quality of the patch inductance, choose the patch inductance and what to pay attention to what problems? First of all, the selection of patch inductor should first consider its specific application of occasion, function, circuit requirements, environment and cost and other factors. If we are not professional technical personnel, usually do not know much about the chip inductance specifications and models, it is difficult to accurately measure the quality of the chip inductance. So let's introduce you to how to measure the inductance of the patch!


First, we need to mark the inductance of the patch. There are two methods for marking, one of which is the direct marking method and the other is the color marking method. The Direct marking method refers to marking the inductance of the inductor coil directly with numbers and words on the shell of the inductor coil, allowing error and major parameters such as large working current. In the color scale method, the inductance is represented by a color ring, the unit is mH, the first two digits represent the significant digits, the third digit represents the multiplier, and the fourth digit represents the error.


Then we need a multimeter. First set the multimeter to the buzzer secondary stop, then put the marker on both ends, and then we can watch the multimeter reading. If the multimeter reads too large or infinite, the patch inductance is damaged, because a normal patch inductance should read zero. But for the inductor coil turns more, wire diameter of the coil number, we will find that the reading will reach dozens or hundreds, but usually the coil DC resistance is only a few ohms. The damage is also shown as burning or obvious damage to the inductor magnetic ring. If the inductor coil is not seriously damaged, leading to an accurate judgment, we can choose to use the inductance meter to measure its inductance or use the replacement method to judge.


When measuring the inductance of the patch, we should pay attention to several problems. For example, the core and wire winding are easy to change the inductance because of the effect of temperature rise. It should be noted that the temperature of the body must be within the range of the specification. Second, the winding is easy to form an electromagnetic field after the current passes through. Therefore, attention should be paid to the distance between the inductors, the winding group can be at right angles to each other, reducing the amount of induction between each other.


The above is about how to measure the quality of the patch inductance and precautions; in fact, we often say that the inductance of the patch inductance is the inductance of the conductor through the AC current, in and around the wire to produce alternating flux, wire magnetic flux and the current of the production of the flux. Inductance is only a parameter related to coil number, size, shape and medium. It is a measure of inductance coil inertia and has nothing to do with the applied current.


 CD31-105 Patch Electrosensing
1. SHAPE AND SIZE of five rings (unit mm)  


Five ring number A B C D  ref
CD31 3.5±0.3 3.0±0.3 1.1±0.2 0.8 
CD32 3.5±0.3 3.0±0.3 2.0±0.3 0.8 
CD43 4.5±0.3 4.0±0.3 3.2±0.3 1.5 
CD52 5.8±0.3 5.2±0.3 2.5±0.3 1.7 
CD53 5.8±0.3 5.2±0.3 3.0±0.3 1.7 
CD54 5.8±0.3 5.2±0.3 4.5±0.3 1.7 
CD73 7.8±0.3 7.0±0.3 3.5±0.5 2.0 
CD75 7.8±0.3 7.0±0.3 5.0±0.5 2.0 
CD104 10.0±0.3 9.0±0.3 4.0±0.3 2.5 
CD105 10.0±0.3 9.0±0.3 5.4±0.3 2.5 
CD108 10.0±0.3 9.0±0.3 8.0±0.3 2.5 
CD137 13.0±0.3 12.0±0.3 7.0±0.3 3.0 
CD2017 20.0±0.3 19.0±0.3 17.0±0.3 3.0 
2. Five ring numbers
CD    75    -   221     K
(1)       (2)           (3)     (4)
(1). Type: CD31/32/43/52/53/54/73/75/104/105 ( CD )
(2). Size: According to size ( 75 )
(3). Inductance: Example: "221"for 220uH ( 221 )
(4). Tolerance:"M:±20%, "K":±10% , "J":±5%  ( K )