The selection of fixed resistors:
The fixed resistors have a variety of types. Which material and structural resistors should be selected, and should be determined according to the specific requirements of the application circuit.
High frequency circuitry should use non-wire-wound resistors that distribute inductors and distributed capacitors, such as carbon film resistors, metal resistors, metal oxide resistors, thin film resistors, thick film resistors, alloy resistors, anti-corrosion coating Resistors, etc. High gain small signal amplifying circuits should be used with low noise resistors, such as metal film resistors, carbon film resistors, and wire resistors, and noise larger synthetic carbon film resistors and organic heart resistors.
The wire winding resistor has a large power, small current noise, high temperature resistance, but is large. Ordinary wire wind resistors are commonly used in low frequency circuits or a deflector resistor, a voltage resistor, a barrel resistor or a high power tube. The high precision wire wind resistor is mostly used in fixed attenuators, resistance 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 should prefer the standard series resistor. The resistor used in the general circuit allows the error to be ± 5% to ± 10%. Precision instruments and resistors used in special circuits should use precision resistors, resistors within 1%, such as 0.01%, 0.1%, 0.5% of these amounts of electrical resistance, should be used in Jet. The rated power of the selected resistor must comply with the requirements of the resistor power capacity in the application circuit, generally should not increase or reduce the power of the resistor. If the circuit requirements are power-type resistors, their rated power can be higher than 1 to 2 times the actual application circuitry.