Choosing the appropriate material and structure of resistors has troubled many engineers for years. When designing electronic circuits, the type and error level of resistors should be selected according to the technical specifications of the electronic equipment, the specific requirements of the circuit, and the characteristic parameters of the resistor. The following guide has been compiled to assist in selecting resistors:

1. High-frequency circuits should use non-wirewound resistors with minimal distributed inductance and capacitance.

2. Ordinary wirewound resistors are often used in low-frequency circuits or as current limiting resistors, voltage divider resistors, bleeder resistors, or bias resistors for high-power tubes. Wirewound resistors with higher precision are mostly used in fixed attenuators, resistor boxes, computers, and various precision electronic instruments. The resistance value of the selected resistor should be close to a nominal value of the calculated value in the application circuit, and standard series resistors should be preferred. The allowable error for resistors used in general circuits is ±5% to ±10%. Resistors used in precision instruments and special circuits should be precision resistors.

3. Select the rated power consumption of the resistor based on the actual load power consumption that the resistor bears in the working circuit. When the ambient temperature exceeds the rated ambient temperature, refer to the power reduction curve to reduce the load power consumption. The rated power of the resistor should meet the power capacity requirements of the application circuit. Generally, the power of the resistor should not be increased or reduced arbitrarily. If the circuit requires a power resistor, its rated power can be 1 to 2 times higher than the power required by the actual application circuit.

4. When high pulse current, surge current, or crosstalk current from other components is a concern, consult with the manufacturer in advance to determine if flame-retardant resistors are necessary. General resistors are not flame-retardant and may exhibit combustion, gas emission, smoke, or red heat when overloaded. Flame-retardant resistors, on the other hand, may produce smoke and red heat when the power exceeds the specified value but will not catch fire or combust.

5. Select the accuracy and nominal resistance of the resistor according to the needs of the working circuit. The chosen nominal resistance should preferably match a value in the standard resistance series.

6. When selecting a resistor, ensure that its limit voltage meets the circuit's requirements to avoid breakdown due to voltage limitations.

7. Measure and check the resistor before installation, especially for high-requirement applications. Artificial aging treatment may be necessary to improve stability.

8. Choose different types of resistors based on the circuit's operating frequency.