When you need to buy a precision resistor for a specific application, you will need to find out its nominal value and its temperature drift index. Resistors are soldered to PCBs before they are rated, and temperature drift index measurement is very expensive and can damage the product. The tolerance value of the resistor will determine the accuracy of your circuit. There are several different types of resistors available, including wirewound, metal film, foil, bare metal, and thin film, each of which has different results. The temperature coefficient is a measurement that describes how much the resistance changes with a change of 1 degree in temperature. As such, if a resistor increases one degree in temperature, its value drops by 110 ppm, which is approximately 1.1 ohms for every ten-thousandth of a million.
A high-precision resistor is labeled with an extra band that indicates the third significant digit. You can also look for the multiplier factor or the tolerance of a precision resistor. The higher the tolerance, the more accurate it is. Precision resistors are usually more expensive than ordinary ones, but they're worth the extra money for the precision they provide. The price difference is a reflection of the higher-quality materials used to make them.
When buying a precision resistor, you can choose from several different types. One type is made of carbon, which is the most common type of composition. Another type is made of plastic, which is a relatively inexpensive general-purpose resistor. While it's not as reliable as a metal-core precision resistor, it can be extremely useful in many applications. You can also choose between different materials to make a precision resistor, such as a ceramic one.
A Precision resistor has many advantages. The simplest form is a four-pin structure. A four-pin structure facilitates precision sampling. The size is a factor in price, as it requires more power space. You can also add an auxiliary radiator to lower the surface temperature and increase the stability of the sampling resistor. It's also advantageous to use precision resistors instead of Hall current sensors in applications that require high accuracy.
The accuracy of a precision resistor is important when deciding which type to buy. Ideally, it should have a temperature drift of less than five ppm per degree C. If the resistor is soldered to a PCB, its accuracy could be reduced by as much as 300 ppm. However, it is still important to consider stability when buying a precision resistor, as high accuracy is not as important as its stability.
A High-voltage Metal Film Resistor is a good choice for high-voltage applications, but there are other considerations. Precision resistors must be matched precisely to the circuit. If you choose a resistor without these criteria, it won't be as accurate as a high-voltage resistor. It is also possible to buy a resistor without matching tolerances. A precision resistor should be available from a reliable source.
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