Current Sense Shunt Resistors

Shunt resistors are typically used in electrical circuits for measuring current flow. They dissipate power when they are not in use, and they are ideal for low-voltage applications. Their resistance value is low and their temperature coefficient of resistance is low, so they provide an accurate measurement. In addition, they are RoHS compliant, which means that they are environmentally friendly. In addition, they are practical and cost-effective solutions to current flow measurement. 

The size and shape of the footprint are important for accuracy. The optimal footprint is C for a high accuracy measurement. The dimensions of the footprint are shown in Figure 6. The orientation of the sensor trace is also important for measurement accuracy. A shunt resistor with an inappropriate resistance will disrupt the system and reduce the voltage available to drive the load. A shunt resistor with a small resistance value will not be as accurate.

In many applications, a Current Sense Resistor is used to measure current. Its name derives from the fact that it senses current when it flows through it. These devices have two pairs of electrodes, one on the inner side, and one on the outer side. The inner side of the electrodes is used to measure current, and the outer edge of the pads is used to detect heat. A Current Sense Shunt is also commonly used in power circuits, as it can be placed anywhere in the circuit.

The shunt resistor is not as simple as it appears. It has three separate resistances: the shunt resistor itself, its leads, and the printed circuit board's lead. The shunt is a low-resistance path, and the voltage drop across the shunt resistor is directly proportional to the current flowing through it. Hence, the voltage drop is directly proportional to the current flow, and the greater the current, the lower the resistance of the shunt resistor. Therefore, a small-value resistor can overrule an extra heat sink.

The shunt resistor's tolerance plays a key role in its sensing accuracy. A Hall Effect Sensor Shunt resistor with a tolerance of 10% will have a value between nine and eleven Ohms. Its value will vary with ambient temperature and other dependencies. Nonetheless, in most applications, this is of little concern. If the shunt resistor has a low tolerance, it is not safe to use.

While it may seem straightforward to measure the voltage across a known resistor, several factors can influence the measurement accuracy. The best placement for a shunt resistor depends on its value and tolerance. A shunt resistor should be high-side placed across a positive rail. If you want to know more about this topic, then click here: https://en.wikipedia.org/wiki/Shunt_(electrical).