The importance of 0 ohm resistance, PCB engineering must know

1 : no function is provided in the circuit. It is only for convenience of debugging or Compatibility Design on the PCB.
2 : Jumper can be used. If a line is not used, do not paste the resistor directly (without affecting the appearance)
3 : when the matching circuit parameters are uncertain, use 0 ohm instead. during actual debugging, determine the parameters, then, it is replaced by a component of a specific value.
4. when you want to test the current consumption of some circuits, you can remove the 0ohm resistor and connect the current meter to facilitate the current consumption test.
5 , you can also add a 0 euro resistor
6 to act as an inductor or capacitor under a high-frequency signal. Inductance is used to solve EMC problems. For example,
7 between the ground, power supply, and IC pin. Single Point Grounding (that is, protection grounding, work grounding, and DC grounding are separated from each other on the equipment, independent Systems .)
8 , fusing effect

* single point grounding in analog and digital locations *
as long as it is a land, it is eventually connected together and then entered into the earth. If it is not connected together, it is "floating", there is a pressure difference, it is easy to accumulate the charge, resulting in static electricity. The ground refers to the 0 potential, and all voltages are obtained from the reference ground. The ground standards must be consistent, so all kinds of ground should be transient together. People think that the earth can absorb all the charge and always maintain stability, which is the final reference point. Although some boards are not connected to the earth, power plants are connected to the earth, and the power supply on the boards will eventually return to the power plant. If the simulated area is directly connected to the digital area, mutual interference will occur. There are four ways to solve this problem: 1. Connect with magnetic beads; 2. Connect with capacitors; 3. Connect with inductor; 4. Connect with a 0 ohm resistor.
the equivalent circuit of a magnetic bead is equivalent to a band-blocking wave limiting device, which can only significantly reduce the noise at a certain frequency point. It is necessary to estimate the noise frequency in advance to select an appropriate model. Magnetic beads do not match when the frequency is uncertain or unpredictable.
the capacitor is separated directly, causing float.
the inductance is large in size, with many stray parameters and unstable.
0 euro resistance is equivalent to a very narrow current path, which can effectively limit the Loop Current and suppress noise. Resistance degrades in all frequencies (0 euro resistance also has impedance), which is stronger than magnetic beads.
* used for current loop during cross-connection *
when the electrical ground plane is split, the shortest backflow path of the signal is broken. At this time, the signal loop has to bypass to form a large loop area, the influence of the electric field and the magnetic field becomes stronger, and it is easy to interfere with/be disturbed. The split zone is connected with 0 euro resistance, which can provide a shorter reflux path to reduce interference.
* configuration circuit *
generally, patch cords and dial switches are not allowed on the product. Sometimes users may tamper with the settings, which may cause misunderstanding. In order to reduce maintenance costs, use 0 euro resistance instead of jumper and other welding on the board.
A vacant patch cord is equivalent to an antenna at a high frequency. It works well with SMD resistors.
* Other Purposes * cross-line cabling
debugging/testing
temporarily replacing other SMD devices
As a temperature compensator
out of EMC countermeasure needs. In addition, the 0 ohm resistance is smaller than the parasitic inductance of the passing hole, and the passing hole will also affect the ground plane (because the hole needs to be dug