First, the selection of fuse resistor The fuse resistor has a protective function. The dual performance should be considered when selecting it, and its resistance and power parameters should be selected according to the specific requirements of the circuit. It is necessary to ensure that it can blow quickly under overload, and that it can work stably for a long time under normal conditions. If the resistance value is too large or the power is too large, neither can protect it.
Second, the selection of fixed resistors There are many types of fixed resistors, which type of material and structure resistor to choose should be based on the specific requirements of the application circuit. High frequency circuits should use non-wire wound resistors with small distributed inductance and distributed capacitance, such as carbon film resistors, metal resistors and metal oxide film resistors.
High-gain small-signal amplifier circuits should use low-noise resistors, such as metal film resistors, carbon film resistors, and wire-wound resistors. Synthetic carbon film resistors and organic solid resistors with high noise cannot be used.
Wirewound resistors have large power, low current noise, high temperature resistance, but large volume. Ordinary wire-wound resistors are often used in low-frequency circuits or mid-range current-limiting resistors, voltage-dividing resistors, bleeder resistors, or bias resistors for high-power tubes. High-precision wire-wound resistors are mostly used in fixed attenuators, resistance boxes, computers, and various precision electronic instruments.