Shunts, Jumpers
1. Shunts Overview
1) Functional Definition
Shunts usually refer to low-resistance resistors used for current detection or path shunting. Its core function is to indirectly calculate the current value in the circuit by measuring the voltage drop across the resistor, which is common in high-precision current monitoring systems.
2) Parameter Characteristics
Resistance Range: Usually in the milliohm level (mΩ), for example, the standard shunt resistance is generally less than 50mΩ.
Power and Package: The package size (such as 0805, 0603) directly affects the rated current-carrying capacity. For example, Shunts in the 0805 package usually support higher continuous current than 0603.
Accuracy Requirements: In high-precision scenarios, it is necessary to select specifications with smaller errors (such as 1% accuracy) to avoid measurement deviations.
3) Application Scenarios
Mainly used in systems that require real-time current feedback, such as power management, battery charge and discharge monitoring, and motor control.
2. Jumpers Overview
1) Functional Definition
Jumpers are circuit path switching components implemented through physical connections or 0Ω resistors, and are often used for hardware debugging, function configuration, or signal jumps.
2) Implementation Form
0Ω Resistor: A jumper resistor for surface mount (such as 0603 package), with an extremely low actual resistance (usually <50mΩ), which has both jumper function and overcurrent protection characteristics.
Physical Jumper: Such as plug-in short-circuit caps (Jumper Cap), which directly conduct the circuit through metal pins.
3) Selection Points
Current Capacity: It needs to be selected according to the package size. For example, the rated current of the 0Ω jumper resistor of the 0603 package is generally 1A, while the rated current of the 0805 can reach 2A.
Withstand Voltage Level: Different packages correspond to different withstand voltage values, and it is necessary to avoid breakdown due to excessive voltage.
4) Typical Applications
Noise isolation in single-point grounding design.
Function module bypass or signal test point connection during PCB debugging.
3. The Relationship and Difference between Shunts and Jumpers
|
Comparison Items |
Shunts |
Jumpers |
|
Core Functions |
Current detection and shunt |
Circuit path switching and connection |
|
Resistance Characteristics |
Extremely low resistance (mΩ level) |
Approaching 0Ω (actually mΩ residual resistance) |
|
Design Goals |
Accurate Measurement |
Flexible configuration |
|
Typical Packages |
High-power packages (such as 2512) |
Miniaturized packages (such as 0603, plug-in) |
By properly selecting Shunts and Jumpers, engineers can achieve high-precision current management and flexible functional configuration in circuit design, while optimizing PCB layout space.
4. Shunts, Jumpers FAQs
1) What is a flexible jumper?
Flexible jumpers are composed of flexible wires and matching hardware. They are mainly used to realize the electrical connection of wires in different sections in overhead transmission lines. They are widely used, especially when complex electrical gaps need to be handled in locations such as tension towers.
2) What is the role of jumpers in transmission lines?
Used to balance electrical parameters and prevent induced electrical interference (such as short-circuiting tension insulators when constructing adjacent high-voltage lines);
Replace traditional rigid connections to adapt to deformation caused by line swing or thermal expansion and contraction.
3) What issues should be paid attention to when installing jumper cables (jumpers)?
Material Selection: Select vibration-resistant, waterproof, and sealed cable connectors according to the application scenario (such as high-speed rail, floating platform);
Force Direction: When setting the anchor cable, the excavated “horseway” must be consistent with the force direction to ensure stability;
Dynamic Analysis: Floating jumper cables must consider the impact of dynamic loads such as water flow and waves on cable length and tension.
4) How to replace old jumpers?
If there is a high-risk area, such as a railway below, it is necessary to consult with relevant units and use the method of pulling the old line with the new line to replace it, and remove the components that slide into the gear (such as an anti-vibration hammer).
5) Why may jumpers generate static electricity or induced electricity?
When constructing near high-voltage lines, unshorted tension insulators will accumulate charges due to electromagnetic induction, which need to be released by short-circuiting conductors;
Non-conductive materials such as wooden crossing frames are prone to static electricity due to electric field induction in high-voltage environments.
6) How to avoid jumper cable connector failure?
Use built-in airbags or variable-diameter sealing rings to improve waterproof and seismic performance;
Regularly check the cable sheath and grounding system to prevent leakage caused by insulation aging.