Precision resistor: precision resistor is often used in electronic circuits, referred to as precision resistor for short. Precision resistance refers to the resistance whose engineering indexes such as resistance value error, thermal stability (temperature coefficient), resistance distribution parameters, distributed capacitance and distributed inductance) meet certain standards. Let's understand the characteristics of precision resistance!
Precision resistor
Precision resistor: precision resistor is often used in electronic circuits, referred to as precision resistor for short. Precision resistance refers to the resistance whose engineering indexes such as resistance value error, thermal stability (temperature coefficient), resistance distribution parameters, distributed capacitance and distributed inductance) meet certain standards. Let's understand the characteristics of precision resistance!
Characteristics of precision resistor:
1. The required resistance error is the resistance range that reaches a certain standard in the research process. Therefore, in the use of the circuit, the effect is very good and its function is also very favorable.
2. From the beginning, because it can be used in many high and low temperature conditions. The thermal stability of precision resistance is also relatively strong, which can be better used in such a precision range.
3. The distribution parameters meet the relevant standards for the production of these products, i.e. various indicators such as capacitor and inductance, which is relatively simple to use.
The above contents are the basic characteristics of precision resistance. High reliability, large power margin, low temperature rise, low noise, small series inductance, small distributed capacitance, small voltage coefficient, small changes in welding, vibration and elongation. In addition to the basic characteristics, good precision resistance also has the characteristics of small aging, small temperature rise and small deviation.
According to different materials, the distribution parameters of temperature coefficient and resistance value are slightly lower; Winding precision resistance has high resistance value accuracy and temperature coefficient index, including metal film precision resistance, winding precision resistance and metal foil precision resistance. The resistance accuracy of metal film is high, but the distribution parameter index is low. The precision resistance precision, temperature coefficient and distribution parameter index of resistance value of metal foil are very high: the price of the above three precision resistors will increase with the improvement of performance, so they must be reasonably selecte according to the actual application. The accuracy can reach 10-6 and the temperature coefficient can reach 0.3 times; 10-6 /, the distributed capacitance can be less than 0.5pf, and the distributed inductance can be less than 0.1h. For example, in low-frequency DC and AC circuits, winding precision resistors and metal film precision resistors are usually selecte instead of expensive metal foil precision resistors.
The main body of metal film precision resistor is usually cylindrical; When the number of turns of the winding precision resistor is large, in order to reduce the distributed inductance as much as possible, the rectangular winding precision resistor is usually customized by the equipment manufacturer according to the needs, which is often used in instruments and meters. The winding is mainly non inductive. Winding precision resistors have cylindrical, flat cylindrical and rectangular frame shapes; The precision resistance of metal foil is mainly block or sheet. The number of turns of the forward winding and the revers winding are the same.
After the rectangular frame winding in the instrument is damaged, just remove the original resistance wire from the frame and dip it again (1260 insulating paint with good performance and low price should be selecte). It can be replaced by evenly winding a new alloy resistance wire with the same material, diameter and length as the original resistance alloy wire on the original frame. If the precision resistance wound by the original rectangular frame wire is only damaged on the surface insulation layer, it can be wound back to the original rectangular frame after drying.
Scheme recommendation: tianer compact resistor
