An ammeter shunt is a specialized resistor used to measure high currents in electrical circuits. It operates by providing a low-resistance path for a portion of the current, allowing the measurement of large currents that would exceed the limits of a standard ammeter.

 Key Features of Ammeter Shunts

1. Functionality: The primary purpose of an ammeter shunt is to bypass most of the current, allowing only a small, measurable portion to flow through the ammeter. This is achieved by placing the shunt in parallel with the ammeter. The voltage drop across the shunt is then measured, and the current is calculated using Ohm's Law:    I = \frac{V}{R

2. Resistance Values: Ammeter shunts typically have very low resistance values, often in the milliohm range (e.g., 0.5 mΩ or lower). This low resistance minimizes power loss and heat generation during operation, making them suitable for high-current applications[4][5].

3. Voltage Ratings: Shunts are rated for specific voltage drops at maximum current levels, commonly at 50 mV, 75 mV, or 100 mV. For instance, a shunt rated for 100 A with a 75 mV drop would have a resistance of 0.75 mΩ. This means that when 100 A flows through the shunt, the voltage drop across it will be 75 mV, which can be measured by the ammeter.

4.Material Composition: Ammeter shunts are often made from materials like manganin, which have a low temperature coefficient of resistance. This ensures stable performance and accuracy across a range of temperatures.

5. Installation Considerations: The placement of the shunt within the circuit is crucial. It is often recommended to install the shunt as close to the ground as possible to protect the ammeter from high common-mode voltages. Alternatively, shunts can be placed in the ungrounded leg of the circuit, but this requires careful insulation to handle the full circuit voltage.

Applications of Ammeter Shunts

- High-Current Measurement: Ammeter shunts are essential in applications where the current exceeds the measuring capacity of standard ammeters, such as in industrial machinery, battery management systems, and electric vehicles.

- Overcurrent Protection: They can also serve as protective devices by allowing for the detection of overcurrent conditions, triggering alarms or shutting down systems to prevent damage.

- Precision Measurement: In laboratory settings, high-precision shunts are used for accurate current measurement, often with specifications in the parts-per-million range for resistance stability over time.

In summary, ammeter shunts are vital components for accurately measuring high currents in various electrical applications, providing a reliable means to monitor and control electrical systems.

	Features
	●The resistor body is made of manganese copper alloy material welded by high energy electron beam ●High precision, high strength, high stability and high reliability
	●The resistor body is used entirely as a measuring resistor, resulting in low heat generation and low surface temperature rise ●Proprietary process technology can produce extremely low resistance resistors
	Resistance changes with temperature
Resistance change percentage		0.5 0.0 -0.5 -1.0l        -40-20         0       20      40        60                100120140
Application Areas
●It is mainly used as sampling resistor in electronic watt-hour meter. The structure design is flexible and can be designed according to customer requirements.
Product Structure
Product size
	Resistor value		Current capacity	Accuracy	Temperature coefficient
	120uQ		60A-150A	±5% ±10%	≤±50ppm/C
	150uQ
	175uQ
	200μQ
	250μQ
	300uQ
	320μQ
	500μQ
	Resistors can be designed and produced according to customer requirements

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