【School】】 0 ohm resistors weak role..

<br> 1, no function in the circuit, but on the PCB for debugging reasons of convenience or compatible design. .<BR> 2, can be done with a jumper, if you do not have a certain line, is not attached directly to the resistor (does not affect appearance) <BR> 3, uncertainty in the match when the circuit parameters to 0 ohms instead of the actual debugging .time, determine the parameters, then the specific value of the components instead. .<BR> 4, a part of the circuit to measure current consumption, they can remove 0ohm resistor, connected to the ammeter, so easy to measure current consumption. .<BR> 5, in the wiring, if the fabric is not passed, you can also add a 0 ohm resistor <BR> 6, in the high frequency signal, acting as inductors or capacitors. .(With external circuit characteristics related) inductors used mainly to solve the EMC problem. .As with land, power and IC Pin between the <BR> 7, single-point ground (refer to protective earth, working ground, DC ground is separate from the device, each as an independent system.) <BR> 8, fuse function * Analog .and digital ground single-point ground * <BR> as long as the ground, will eventually be wired together, and then into the earth. .If you do not take them all together, "Floating", there is pressure, easy to accumulate charge, causing static electricity. .In reference to 0 potential, all voltages are reference to come, and to the standards to be consistent, so all kinds of places should be shorted together. .People think the land can absorb all the charges, has remained stable, is the ultimate reference points. .Although some board did not take the land, but power plants are connected to the earth, the board will eventually return to the power plant into the ground. .If the analog and digital ground is directly connected to a large area will cause interference. .Not less then and wrong, there are four reasons as above to resolve this problem: <BR> 1, with the beads connected; <BR> 2, with a capacitor connected; <BR> 3, inductively connected; <BR> 4, .Connect with 0 ohm resistors. .<BR> Bead equivalent circuit equivalent to band-stop filter limit, only the noise of a frequency significantly inhibited the use of pre-estimated noise frequency is required in order to select appropriate models. .The frequency of uncertain or unforeseen circumstances, beads substandard. .<BR> Capacitor through every intersection, causing floating. .<BR> Bulky inductors, stray parameters and more unstable. .<BR> 0 ohm is equivalent to a very narrow current path, can effectively limit the loop current, the noise is suppressed. .Resistance in all frequency bands are attenuation (0 ohm impedance also), this is stronger than the magnetic beads. .<BR> * Time span for the current power circuit * <BR> when the split ground plane, the resulting signal is the shortest path to break back, this time, the signal circuit had to pass, forming a large loop area, the electric and magnetic fields .effect becomes strong, easy to interference / tampering. .On the partition 0 ohm jumper, can provide a shorter return path, reducing the interference. .* Configuration circuit * <BR> general, the products do not appear on the jumpers and DIP switches. .Sometimes the user will tamper with settings, easy to be misunderstood, in order to reduce maintenance costs, the application instead of 0 ohm jumper on the board and other welding. .<BR> Vacant jumper at high frequencies is equivalent to the antenna, chip resistors with good results. .* Other uses * <BR> wiring across the line <BR> debugging / testing device <BR> <BR> temporary substitute for other chip temperature compensation device as <BR> more often the need for EMC countermeasures. .In addition, the 0 ohm resistor parasitic inductance than through a small hole, and through-hole also affects the ground plane (because of the need to dig holes)..