Resistors are devices, which restricts current flow to a particular level. Resistors having a high value of resistance will surely hold back more current compared to the resistors with low value resistance.
Transistors, LEDs, as well as other semiconductor devices are usually highly sensitive to any electric current. This means destruction with very high current, but very little current will also prevent their effective functioning.
Resistors having the right value placed into the circuit will allow transistors, LED, as well as other semiconductor devices to function in an electric current range, which suits them appropriately.
However, what about the 0 ohm resistors which come with a resistance of almost zero. 0 ohm resistors lack the ability to restrict current flow; so what is a zero-ohm resistor used for in a circuit?
Since 0 ohm resistors cannot restrict current flow, it cannot serve as a usual resistor. This type of resistors is useful in printed circuit boards for a unique purpose. In this article, we will be answering questions such as: What is a zero-ohm resistor? What is a zero-ohm resistor used for? Reasons why 0 ohm resistors are necessary for you? And more! Please join us as we explain further.
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What is a Zero-ohm Resistor?
The 0 ohm resistor is just exactly the way you call it. This refers to a single resistor possessing a resistance of zero ohms after measurement. Through-hole resistors having zero ohms are usually marked using a black band that tells the resistance’ value.
Meanwhile, the surface mount type of ceramic resistor comes with just one or multiple zeros to indicate the 0 ohm resistance. Furthermore, you can see a zero-ohm resistor as a jumper wire, with shaping similar to that of typical resistors. Using a multimeter to measure a 0 ohm resistor will give a reading, which approaches 0 ohm.
What is a Zero-ohm Resistor Used For?
Any PCB designer that has never come in contact with a zero-ohm resistor usually has a lot of questions in mind as regards the component’s practicability and application. After all, what’s the need of going through so much stress manufacturing zero-ohm resistors when you could use jumper wires during the design?
Single Layer Design
Printed circuit board designers are usually pressurized to reduce cost. It is very cheap when you confine a design into a PCB with a single layer. However, it is tough to get these traces to its destination without any overlapping, especially when there are some components present.
A zero-ohm resistor is a great remedy to route a one layer board. Instead of you making holes and transforming the printed circuit board into a structure with a double layer, you can just go ahead to route the trace between the 0 ohm resistor’s pads.
You can then assemble the resistors coupled with all other components during the process of manufacturing.
It is normal to create or build circuits using jumpers, which permits some subcircuits to connect flexibly. Usually, you can replicate some product variations where you use just some subcircuits. 0 ohm resistors are useful in replacing jumpers, as well as making certain PCB connections possible.
For PCB building using manual soldering and placement, making use of a jumper wire is most probably the most effective way for establishing connections between the pads. Moreover, with mass production, you need a machine called pick-and-place. This lacks the ability to unroll and cut jumper wires. For cases like this, you will need another machine for the jumper wires.
To produce large, you have to keep the required cost on a low. Making use of another machine just for the jumper wires leads to a different process cost and setup. This is why a 0 ohm resistor is the best option, which helps you save time and cost during assembly.
Prevention of Reverse Engineering
There’s no doubt. There are people in the market simply acting as copycats that are ready to copy or engineer printed circuit boards that have come out successful. Without coating the whole printed circuit board with epoxy, 0 ohm resistors are usually a good option that helps in confusing any unethical copycat.
When you place the 0 ohm resistor on some tracks is a great strategy in misleading any perpetrator in imitating the design. Also, if you can, order 0 ohm resistors having no markings. This will help you frustrate the efforts of these copy cats even more.
Design Consideration When Making Use of Zero-Ohm Resistors
The process of utilizing a 0 ohm resistor shouldn’t come complicated. However, there’s a need to remember that the 0 ohm resistors are not ideal components. What we mean is that, it possesses some resistance just like other conductive traces and wires.
Since a 0 ohm resistor possesses a little resistance, it has the ability to dissipate heat anytime current passes through. Furthermore, you can define the highest power rating of 0 ohm resistors by the material’s thermal characteristic and the size. Also, you will want to ensure that you have a 0 ohm resistor, which will easily handle the current that passes through, without having to burn out.
Whether it serves to protect the design or automate your assembly process fully, you can easily add 0 ohm resistors if you have some software for PCB design in your possession like the OrCAD PCB Designer. You will wonder how this tiny component, which has confused so many people, could lead to substantial savings in cost. Furthermore, the entirety of Cadence’s PCB analysis and design tools can aid your design process to help excel in any given scenario.
What are the Benefits of 0 Ohm Resistors?
0 ohm resistors are very useful in technology and circuit design. Below are the benefits of 0 Ohm resistors.
Convenient and easy wiring
The main reason why 0 ohm resistors are useful is because most PCB components are usually placed using machines for automatic insertion. There are cases where it becomes necessary to reduce two PCB points, in which wires would be normally between these points.
However, these insertion machines may only work for components like resistors, but not jumper wires. You have to use a different jumper wire machine to insert these jumper wires, or someone can install the jumper wires manually. However, rather than follow this process, 0 ohm resistors are useful.
The 0 ohm resistors are important in that you can remove them easily compared to the jumper wires. Furthermore, if you need to make changes after doing the design, you can easily remove the 0 ohm resistor and a new component inserted to take its place.
Debugging and Circuit or PCB Board’s compatibility
During PCB design, there’s a need to consider the compatibility seriously. This is because you fix PCB boards physically after printing it physically and allowing it to undergo copper processing. If you fail to consider the compatibility issue in your design, the engineer will face much inconvenience during the PCB board’s debugging phase.
Here, 0 ohm resistors play a major role during the PCB board’s debugging. This is because they are useful in connecting the PCB traces.
For instance, a microchip pin has two major functions. These include driving an LED and driving a buzzer. However, the issue with this is that both functions will not work at once. Therefore, to realize the period for driving on one circuit board, you can add 0 ohm resistance to that line connecting the LED light and the buzzer.
Measures current conveniently
After you have designed your circuit system, there’s a need to test the whole circuit’s power consumption during operation. This practice is conventional and useful in calculating the consumption of power. This is possible by taking current measurements and then using the voltage and current you’ve measured in determining the consumption of power. Here, methods for determining current most times involve measuring the circuit’s current making use of current instruments.
Now, if you place 0 ohm resistors where you need to measure the current, then you will remove the resistor when you need the measurement, and you connect either the multimeter or ammeter. To ensure that it operates normally, you should solder it to the 0 ohm resistor directly.
Reserve Resistance Position
If during the design stage of the circuit, a particular position remains unknown, how much resistance do you need to connect to your resistor? When this happens, the resistor’s soldering position can be made to stay in that position, and then you can solder the 0 ohm resistor. In actual debugging of circuits, changing of the resistance is convenient, and then the right resistance is connected after you have debugged the resistance parameter you have determined.
Reduction of Electrical Noise
As a result of the characteristics of a 0 ohm resistor, you can effectively suppress the loop current. By doing so, you are reducing the noise. 0 ohm resistance comes with negligible impedance; this is only achieved by superconductors. Therefore, 0 ohm resistance plays a very significant role in the attenuation of all frequency ranges and bands.
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Ground wire isolation
When designing chips, the analog circuit’s ground is referred to as AVSS, while that of digital circuit is known as VSS. Both the VSS and AVSS are usually separated in the chip. Since you can separate the bottom line, you can prevent the current signals from having any interference while operating the digital and analog circuit.
Serves as a Capacitor Inductor
For high-frequency circuit systems, 0 ohm resistors can serve as a small inductor or capacitor whenever it matches the external circuit’s features that can help in solving the EMC issue appropriately. For example, it can be between the chip pins and power supply or ground and ground.
Effective Operation of the Circuit
Many pins are usually seen on boards and require termination using a jumper cap. Also, the use of the DIP switches in controlling the closure of the circuit. Though both methods are very convenient when debugging, it is advisable to use them very little when producing products. The vacant pins are synonymous to high-frequency circuit antennas; this is why the signal can be disturbed easily.
Furthermore, unsuspecting people can easily disturb the DIP switch. This will cause errors to the circuit system. Therefore, taking safety precautions, you must make use of a 0 ohm resistor rather than a dip switch and pin. With this, maintenance costs will lessen and it can prevent misuse as well.
Frequently Asked Questions
What functions do 0 ohm resistors perform?
A 0 ohm resistor is a form of wire link which is package in a similar package format like the resistor. These resistors play a vital role in the connection of traces on PCBs.
Is it possible to use a wire as a replacement for 0 ohm resistors?
With 0 ohm resistors, you are sure of having many benefits. You can use them like a wire link using the printed circuit board assembly robots to insert them automatically.
A 0 ohm reading means what?
Circuits having no resistance mean complete circuits, or one having no shorts. Circuits having total resistance would mean a circuit that is completely open. A completely open circuit is one where current cannot pass through.
How can I test a 0 ohm resistor?
When working with the components of the resistor like the SMD resistor, 0 resistors simply specify DC resistance, and not AC impedance. A 0 resistor’s accuracy at DC has to be tested making use of an accurate DMM (Digital multimeter) like the 34420A.
With this article, we hope we have been able to answer the question “what is a zero-ohm resistor used for?” Despite the fact they can be replaced easily, using a 0 ohm resistor is important. This is because it plays many important roles in the circuits of printed circuit boards. Furthermore, it is readily available from many online stores. It is reliable and cost-effective. If you have any more questions, always feel free to contact us. We are always here for you.