3,根據常用的加熱管電阻值Ω國標范圍：+5-10％電阻值(公司的標準為:+4-8％計算)=等于出廠電阻，特別說明:按國標是+5-10％,為啥按+4-8％計算,計算時把電阻范圍縮小,就是說:在生產中電阻超出+4-8％范圍,還在+5-10％范圍內,這樣不會出現電阻偏大偏小.電阻下限值: 81.3÷1,04=78.1Ω；電阻上限值: 81.3÷0,92=88.3Ω
In the design, the production process heating pipe, heating pipe resistance value, determines the power of a heater（電熱管功率）, GB stipulates, electric heating tube power error range and an electric heating pipe resistance error range, the following article I will introduce how to calculate the 1 aluminum heating pipe resistance range value, heating in what range of resistance within the tube to comply with the relevant standards.
1: got the customer’s drawings, understand customer requirements: using voltage: 230V, power 650W+5-10%; the electric heating pipe with computer CAD drawing out, calculate the pipe length: 252mm,
2: calculates the current intensity is A and the electric heating pipe resistance value（電熱管電阻值）, I- current intensity of A, P- heat pipe power（電熱管功率） W, V- working voltage V, R- resistance, I=P /U; =650/230=2.83A; R=U/I=230/2.83=81.3.
3, according to the common heating pipe resistance value of Omega GB range: +5-10% resistance value (the company standard: +4-8%) = factory resistance special note: according to national standard +5-10%, why is calculated according to +4-8%, the resistance range is narrow, that is: in the production of resistance beyond the scope of +4-8%, still in the range of +5-10% this will not occur, larger resistance is small. The resistance limit: 81.3 / 1,04=78.1 Ω; resistance limit: 81.3 / 0,92=88.3