1. There is no function in the circuit, only in the PCB for debugging convenience or compatible design and other reasons.
2. Can be used as a jumper, if a section of the line is not used, directly without the resistor can be posted (does not affect the appearance).
3. In the matching circuit parameters are not sure, to 0 ohms instead, the actual debugging time, determine the parameters, and then replace the components with specific values.
4. When you want to measure the current consumption of a part of the circuit, you can remove the 0ohm resistor and connect the ammeter, so that it is convenient to measure the current consumption.
5. In the wiring, if you really can not cloth over, you can also add a 0ohm resistor.
6. Under the high frequency signal, act as an inductor or capacitor. (Related to the external circuit characteristics) inductor with, mainly to solve EMC problems. Such as ground and ground, between the power supply and IC Pin.
7. Single point grounding (refers to the protection ground, work ground, DC ground on the equipment separate from each other, each become independent systems.)
8. Fuse role.
9. The proposed ground and digital ground single point ground.
As long as the ground, the final are to be received together, and then into the earth. If not connected together is the "floating ground", there is a pressure difference, easy to accumulate charge, causing static electricity. Ground is a reference 0 potential, all the voltage is a reference to the ground derived from the standard to be consistent, so a variety of ground should be shorted together. It is believed that the earth can absorb all the charges, always maintain stability, is the ultimate ground reference point. Although some boards are not connected to the earth, but the power plant is connected to the earth, the power on the board will eventually return to the power plant into the ground. If the analog ground and digital ground directly connected to a large area, will lead to mutual interference. Not short connection and inappropriate, the reason as above there are four ways to solve this problem: (1) using magnetic beads to connect.
(1) connected with magnetic beads.
(2) connected with a capacitor.
(3) connected with an inductor.
(4) connected with a 0-ohm resistor.
The equivalent circuit of magnetic beads is equivalent to a band resistance limiter, which only has a significant suppression effect on the noise at a certain frequency point, and it is necessary to estimate the noise frequency in advance in order to choose the appropriate model. For frequency uncertainty or unpredictable cases, the magnetic beads do not fit.
Capacitive isolation through the crossover, resulting in a floating ground.
Inductors are large, with many stray parameters and unstable.
0 ohm resistor is equivalent to a very narrow current path, which can effectively limit the loop current and enable noise suppression. Resistors have attenuation in all frequency bands (0 ohm resistors also have impedance), which is stronger than magnetic beads.
10. Used for current loop when jumpering
When splitting the electrical ground plane, resulting in the shortest return path of the signal is broken, at this time, the signal loop has to be bypassed, forming a large loop area, the electric and magnetic fields become stronger, easy to interfere / be interfered with. In the split area across the 0 ohm resistor, can provide a shorter return path, reducing interference.
11. Configuration circuit
In general, do not have jumpers and dip switches on the product. Sometimes users will mess with the settings, which can easily cause misunderstandings. To reduce maintenance costs, 0-ohm resistors should be soldered on the board instead of jumpers, etc.
Vacant jumpers are equivalent to antennas at high frequencies, and good results with chip resistors.
12. Other uses
Wiring when spanning the line
For debugging/testing
Temporary replacement of other SMD devices
As a temperature compensation device
More often than not, it is needed for EMC countermeasures. In addition, 0 Ohm resistor than the hole through the parasitic inductance is small, and over the hole will also affect the ground plane (because to dig holes).
There are different sizes of 0 Ohm resistors allow different currents, generally 0603 of 1A, 0805 of 2A, so different currents will choose different sizes and is reserved for beads, inductors and other locations, according to the size of the beads, inductors also do package, so 0603, 0805 and other different sizes are available.
