Detailed 0 ohm resistor role

1. There is no function in the circuit, just for PCB debugging convenience or compatible design and other reasons.

2. Can do with jumpers, if some of the lines do not directly do not paste the resistance (does not affect the appearance)

3. Matching circuit parameters are not the time to 0 ohm instead, the actual debugging time, to determine the parameters, and then the specific value of the components instead.

4. To test the current consumption of a part of the circuit, you can remove the 0ohm resistance, connected to the ammeter, so easy to measure the current consumption.

5. In the wiring, if the cloth is not gone, you can also add a 0 ohm resistor

6. Under high-frequency signals, act as inductors or capacitors. (Related to external circuit characteristics) Inductor, mainly to solve the EMC problem. Such as ground and ground, power and IC Pin between

7. Single-point grounding (referring to protective earthing, working grounding, DC earthing are separated from each other on the equipment and each becomes a separate system.)

8. Fuse function

9. To be a single point of grounding and digital ground

Ground is the reference 0 potential, all voltages are obtained from the reference ground to the same standards, so all kinds of ground should be short together. If analog and digital directly connected to a large area, will lead to mutual interference. 

There are four ways to solve this problem:

(1) with magnetic beads connection;

(2) connect with capacitor

(3) with inductance connection;

(4) Connect with 0 ohm resistor.

When used, the frequency of the noise needs to be estimated in advance so as to select an appropriate model. For uncertain or unpredictable frequency, the beads do not fit.

Capacitance across the exchange, resulting in floating.

Large inductor, stray parameters, unstable.

0 ohm resistance is equivalent to a very narrow current path, can effectively limit the loop current, the noise is suppressed. Resistance in all bands have a decay effect (0 ohm resistance also impedance), which is stronger than the magnetic beads.

10. Used for current loop when jumpered

When the electrical ground plane is divided, the shortest return path of the signal is broken. In this case, the signal loop has to be bypassed to form a large loop area. The influence of the electric field and the magnetic field becomes strong and the interference / disturbance easily occurs. Splitting a 0 ohm resistor across the divider provides a shorter return path and reduces interference.

11. Configure the circuit

In general, do not appear on the product jumper and DIP switch. Occasionally, users will be set up, easily lead to misunderstanding, in order to reduce maintenance costs, the application of 0-ohm resistance instead of jumper and other welding on the board.

Vacant jumper at the high frequency equivalent to the antenna, with a patch resistor effect.

12. Other uses

· Crossover when wiring

· Debugging / testing

· Temporarily replace other chip devices

· As a temperature compensation device

More often than not, out of EMC's need. In addition, the 0 ohm resistance is smaller than the parasitic inductance of the via hole, and the via hole also affects the ground plane (because of digging holes).

There is a different size 0 ohm resistance allows the passage of different current, 0603 1A, 0805 2A, so the different current will choose different sizes. There is a place for the beads, inductors, etc., have to be based on beads, inductors The size of the package, so 0603,0805 and so have different sizes