How to Connect a Shunt Resistor Detailed Guidelines and Precautions

In electronic circuit design, shuntingresistanceIt is a commonly used component, mainly used to measure current and shunt voltage. Correctly connecting the shunt resistor not only ensures the accuracy of the measurement, but also protects the safe and stable operation of the circuit. This article will introduce in detail the connection method and related precautions of the shunt resistor to help you better understand and apply the shunt resistor.

1. Basic concept of shunt resistor

A shunt resistor is aLow value resistordevice, usually used to measure current in circuits. Its working principle is to calculate the current through the resistor according to Ohm's law by measuring the voltage drop across the shunt resistor. Since the resistance of the shunt resistor is extremely low, it can effectively reduce the impact on the circuit.

2. Connection location of shunt resistor

Shunt resistors are usually connected to the power line or load line of the circuit, and are commonly connected in series. Specifically, the shunt resistor can be placed at the positive or negative terminal of the power supply, and the safety of the circuit and measurement accuracy should be considered when selecting the location. It is generally recommended to connect the shunt resistor to the negative terminal of the load to facilitate grounding and reduce interference.

3. Select the appropriate shunt resistor value

The resistance of the shunt resistor is generally very small, with common specifications such as 0.01Ω and 0.1Ω. If the resistance value is too large, the circuit voltage may drop, affecting normal operation; if the resistance value is too small, the voltage drop will not be obvious, making it difficult to measure accurately. When selecting, the appropriate resistance value should be determined based on the maximum current and allowable voltage drop of the circuit.

4. Connection methods and wiring techniques

The shunt resistor should be connected using the four-wire measurement method, that is, two wires are connected to both ends of the resistor for current path, and the other two wires are used for measuring voltage. This can avoid the influence of lead resistance on the measurement results. Ensure good contact when wiring to avoid looseness or poor contact causing measurement errors.

5. Pay attention to the power rating of the shunt resistor

The shunt resistor will generate a certain amount of heat when working, so its power level must meet the power demand when the current passes through. Generally, the power of the shunt resistor should be greater than 1.5 times the actual power loss to ensure safe and stable operation.

6. Avoid electromagnetic interference affecting measurement

The measurement voltage of a shunt resistor is usually very small and susceptible to electromagnetic interference. In order to ensure measurement accuracy, the length of the measurement wire should be shortened as much as possible, shielded wires or twisted pairs should be used, and parallel wiring of the measurement wires with high-frequency and high-current lines should be avoided.

7. Safety precautions when connecting shunt resistors

Since the shunt resistor is connected in the circuit, incorrect connection may cause the circuit to short out or damage the components. Before connection, the power supply should be disconnected and the resistance value and power level of the resistor should be confirmed to meet the design requirements; after connection, the circuit should be checked to ensure that it is correct before powering on for testing.

8. Adjustment and calibration in practical applications

After installing the shunt resistor, it is recommended to calibrate it with a known current source to ensure accurate measurement results. Adjust the calculation formula according to the measurement error or replace the shunt resistor with appropriate resistance to improve measurement accuracy.

Shunt resistors play an important role in current measurement and circuit protection. Correctly connecting the shunt resistor requires not only selecting the appropriate resistance value and power level, but also paying attention to the connection method and measurement method to avoid electromagnetic interference and poor contact. Through reasonable design and application of shunt resistors, accurate current measurement can be achieved to ensure the safe and stable operation of electronic equipment. I hope the content of this article can help you better understand and use shunt resistors.