Thin Film Zero Ohm Jumper Resistors

Debugging and compatibility
When hardware engineers design PCB boards, it's important to consider compatibility issues. For example, a certain pin of a chip might have two functions: driving a buzzer or driving an LED. However, these two functions cannot work simultaneously. In order to enable the selection of which module to drive on the same circuit board, a zero-ohm resistor can be added to the circuits connecting the buzzer and the LED. By soldering the thin film zero ohm jumper resistors on either the buzzer's path or the LED's path, engineers can choose to drive either the buzzer or the LED.

Used as jumpers
To reduce wiring complexity, enhance aesthetics, and simplify installation, while avoiding high-frequency interference caused by jump wires.

Bridging circuits during wiring
During the PCB layout and routing phase, there are instances where certain connections cannot be established easily, especially on small boards with numerous connections. In such cases, if a connection requires a lengthy detour to establish, a thin film zero ohm jumper resistors can be used to bridge the previous traces. This doesn't add extra layers and helps reduce the production cost of the PCB.

Reserved for debugging
When circuit parameters cannot be ascertained during parameter matching and practical testing requires removing a resistor or trying different resistance values to achieve an optimal solution, a zero-ohm resistor is typically employed. The zero-ohm resistor is used as a placeholder until the specific parameter values are determined during actual testing, after which it's replaced with actual components of the precise values.
For instance, when there are two different supply voltage options, 5V and 10V, but uncertainty exists regarding whether the different power supply voltages would affect the entire circuit in an unknown way, a zero-ohm resistor is often used to connect them. This allows selecting the power supply connection during circuit debugging.

Measuring circuit power consumption
When unsure about the power consumption of a chip or an entire circuit, a thin film zero ohm jumper resistors can be placed in series with the power supply terminal. After the prototype board is completed, the zero-ohm resistor can be removed, and the two solder points can be directly measured using a multimeter. This measurement helps determine the actual working current, aiding in the calculation of chip or overall circuit power consumption. If you want to measure the current consumption of a specific circuit section, you can attach a zero-ohm resistor and a current meter to facilitate current measurement, which is useful for measuring high currents.

Acting as Capacitors or Inductors in High-Frequency Signals
Under high-frequency signals, a thin film zero ohm jumper resistors, when matched with the external circuit characteristics, can function as a small capacitor or inductor. This can effectively address EMC issues, such as between ground connections or between power supply and chip pins.

Serving as Fuses for Overcurrent Protection
Due to the high fusing current of traces on a PCB, it's challenging for them to fuse during short circuits or overcurrent faults. This might lead to more significant accidents. However, the current-carrying capacity of a zero-ohm resistor is relatively weak, and it would melt first during overcurrent conditions. This action can disconnect the circuit, preventing more substantial accidents from occurring.

Noise suppression
Due to the characteristics of a thin film zero ohm jumper resistors, it can effectively suppress loop currents, thereby attenuating noise. In reality, a thin film zero ohm jumper resistors doesn't truly have zero impedance; only superconductors can achieve true zero impedance. Therefore, a 0-ohm resistor actually provides attenuation across all frequency bands.

A thin film zero ohm jumper resistors looks identical to a standard through-hole or SMD resistor. However, it is constructed to provide the lowest possible resistance, ideally 0 ohms. Key characteristics include:
● Resistance range from 0.0Ω to 0.1Ω typically
● Rated for various power levels per size
● Through-hole, SMD and chip package types
● Act as short circuits or jumpers when soldered
● Provides connection without copper trace
● Lets PCB layout be adjusted post-production
Thin film zero ohm jumper resistors are extremely useful for flexibly bridging connections during prototyping, reworking boards, or adjusting circuit layouts as needed.

Thin film zero ohm jumper resistors are represented on circuit schematics using a standard resistor symbol with the resistance value labeled as 0Ω:
This indicates any location a Thin film zero ohm jumper resistors is used to short two points together in the actual circuit.
On PCB layouts, Thin film zero ohm jumper resistors are denoted using unique layer silkscreen identifiers defined in the legend. Common identifiers include:
● Component overlay: 0Ω
● Top silkscreen: JMP

● Bottom silkscreen: BRIDGE

Band resistor
The four band color code is the most common variation. These thin film zero ohm jumper resistors have two bands for the resistance value, one multiplier and one tolerance band. In the example shown here, the 4 bands are green, blue, red and gold. By using the color code chart, one finds that green stands for 5 and blue for 6. The third band is the multiplier, with red representing a multiplier value of 2 (102). Therefore, the value of this resistor is 56 · 102 = 56 · 100 = 5600 Ω. The gold band means that the resistor has a tolerance of 5%. The resistance value lies therefore between 5320 and 5880 Ω (5560 ± 5%). If the tolerance band is left blank, the result is a 3 band resistor. This means that the resistance value remains the same, but the tolerance is 20%.

Band resistor
Thin film zero ohm jumper resistors with high precision have an extra band to indicate a third significant digit. Therefore, the first three bands indicate the significant digits, the fourth band is the multiplication factor, and the fifth band represents the tolerance. For the example shown here: brown (1), yellow (4), violet (7), black (x 100 = x1), green (0.5%) represents a 147 Ω resistor with a 0.5% tolerance.
There are exceptions to this 5-band color system. For example, sometimes the extra band may indicate failure rate (military specification) or temperature coefficient (older or specialized resistors). Please read the subsection “Color Code Exceptions" below for more information.

Band resistor
Resistors with 6 bands are usually for high precision resistors that have an additional band to specify the temperature coefficient (ppm/˚C = ppm/K). The most common color for the sixth band is brown (100 ppm/˚C). This means that for a temperature change of 10 ˚C, the resistance value can change 1000 ppm = 0.1%. For the 6 band resistor example shown above: orange (3), red (2), brown (1), brown (x10), green (1%), red (50 ppm/°C) represents a 3.21 kΩ resistor with a 1% tolerance and a 50 ppm/°C temperature coefficient.

Remove power from the circuit containing the resistor
This can be done by unplugging it from the mains or by removing the batteries if it is a portable device. Keep in mind that some devices still can be charged with a potentially harmful voltage until minutes after removing its power!

Isolate the resistor from the circuit
An attempt to measure a resistor that is still connected to the circuit can yield an incorrect calculation, as part of the circuit might also be measured.
Disconnect one end of the thin film zero ohm jumper resistors from the circuit. It does not matter which end of the resistor is disconnected. Disconnect the resistor by pulling on the resistor. If the resistor is soldered in place, melt the solder with an electronic grade soldering iron and pull the resistor free using small needle nose pliers. Soldering irons are available at electronic parts and hobby stores.

Inspect the resistor
If the thin film zero ohm jumper resistors shows signs of blackening or charring, it may be damaged by excess current flow. A resistor showing blackening or charring should be replaced and discarded.

Read the resistor value visually
The resistor value will be printed on the resistor. Smaller resistors may have their value indicated by color coded bands.
● Note the resistor tolerance. No resistor is precisely the value indicated on it. The tolerance indicates how much the printed value may vary and still be considered a properly sized resistor. For example, a 1,000 ohm resistor with a 10 percent tolerance indication is still considered to be accurate if it measures no less that 900 ohms and no more than 1,100 ohms.

Prepare a digital multimeter (DMM) to measure the resistor
DMMs are available at electronics parts and hobby stores.
● Ensure that the DMM comes on and does not indicate a low battery condition.
● Set the adjustable scale of the DMM to the next setting higher than the expected resistor value. For example, if the DMM may be set to scales that are multiples of 10 and a resistor marked as 840 ohms is to be measured, set the DMM to the 1,000 ohm scale.

Measure the thin film zero ohm jumper resistors
Connect the 2 leads of the DMM to the 2 legs of the resistor. Resistors have no polarity, so it does not matter which DMM lead is connected to which resistor leg.

Determine the actual resistance of the resistor
Read the result shown on the multimeter. In determining whether or not the thin film zero ohm jumper resistors is within the allowable range for that resistor, do not forget to take the resistor tolerance into account.

Reattach a resistor that gives an accurate reading
Reconnect it to the circuit by pressing it back into place if you pulled it free with your fingers. If the solder joint had to be melted and the resistor had to be disconnected using pliers, melt the solder with the soldering iron and use the needle nose pliers to push the resistor back in to place.

Replace a resistor that measures outside of the acceptable value range
Discard the old resistor. Thin film zero ohm jumper resistors are available in electronics parts stores and hobby stores. Note that replacing the malfunctioning resistor will not necessarily fix the problem, if the resistor fails again the source of the problem should be sought elsewhere in the circuit.