《实用电工电子》模块5直流稳压电源

《实用电工电子》模块5直流稳压电源 模块5直流稳压电源 学习任务 •了解桥式整流、电容滤波和稳压电路 •掌握并联、串联型稳压电路的组成和工作原理 •会安装、测试串联型稳压电源 在工农业生产中，采用的电源主要是交流电。但是在电子线路和自动控制装置中，常常还需要采用电压非常稳定的直流电源。常见的直流电源有蓄电池和干电池，除此之外，目前还广泛地采用各种半导体直流电源。 电子设备中最常用的半导体直流电源是通过把交流电经过整流、滤波和稳压电路变换后而获得的。如图5-1-1所示的就是半导体直流稳压电源的原理方框图。 变压 整流 滤波 稳压 u uuuu 12 3 4 5 u uuuu 12 3 4 5 ttt t t 000 0 0 图5-1-1半导体直流稳压电源的原理方框图 1、电源变压器 电源变压器的作用是将220V的交流电变成合适的交流电以后，再进行交、直流转换。电网上单相交流电的电压有效值为220V，而通常电子电路中需要的直流电压要比此值低。所以，要先利用变压器进行降压。 2、整流电路 整流电路的作用是将经变压器降压后的交流电压变成单向脉动的直流电压。常采用的元件为二极管，经整流电路输出的单向脉动的直流电压幅度变化较大，不能直接供给电子电路使用。 3、滤波电路 滤波电路的作用是滤除整流后单向脉动电压中的交流成分，使之成为平滑的直流电压。arithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. This value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controlled at 110 ? 1 ?. Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen 常采用的元件有电容和电感。 4、稳压电路 稳压电路的作用是使输出电压不受电网电压的波动和负载大小的影响，维持输出直流电压的稳定。滤波后输出的直流电具有较好的平滑程度，但是，此时的电压值还要受到电网电压波动、负载和温度变化的影响而不稳定。为使输出电压稳定，还需要增加稳压电路部分。下面将分别讨论各部分的组成、工作原理和性能。 5.1整流电路 整流电路的主要有单相半波整流电路、单相全波整流电路和单相桥式整流电路。其中，单相半波整流电路最简单，单相桥式整流电路最普遍。 5.1.1 单相半波整流电路 1、工作原理和输出波形 单相半波整流电路如图5-1-2(a)所示，它由整流变压器、整流二极管VD和要求直流供电的负载等效电阻组成。整流变压器，用来将市电220V交流电压变换为整流电路所要求的RL 交流低电压，同时保证直流电源与市电电源有良好的隔离。其中、分别为整流变压器的uu12 原边和副边交流电压。令整流二极管VD为理想二极管。下面分析其工作原理。 u2 VD ωt a 0π2π3π4π + + + R Luu1 2 uo uo , , , b ωt 0π2π3π4π (a)单相半波整流电路 (b)单相半波整流电路的输入、输出电压波形 图5-1-2 单相半波整流电路及其输入、输出电压波形 设整流变压器副边电压为:，当u处于正半周时，其极性为上正下负。u,2Usin(,t)222 i即a点电位高于b点，整流二极管VD正向偏置，处于导通状态。此时流过二极管的电流同D i,iR时流过负载，即。因为整流二极管VD为理想二极管(正向导通电阻为零，而反向0DL u,uu电阻为无穷大)，所以负载两端的输出电压等于变压器副边电压，即，输出电压的020 u波形与变压器副边电压相同。 2 potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 2 当处于负半周时，其极性为上负下正。即a点电位低于b点，整流二极管VD反向偏u2 置，处于截止状态。此时流过二极管的电流=0，输出电流也为0，即负载无电流流i,ii0DD 过，因此，输出电压也为0。此时，全部加到整流二极管两端，它所承受的反向电压=。uuuu02D2电路的工作波形如图5-1-2(b)所示。 由图可见，由于电路只在的正半周有输出，所以称为半波整流电路。半波整流电路结u2 构简单，使用元件少，但整流效率低，理论计算表明其整流效率仅40%左右，输出电压脉动大，因此，它只能用于小功率以及对输出电压波形和整流效率要求不高的设备。 2、参数计算 (1)负载上的电压平均值和电流平均值。输出电压在一个周期内，只有正半周导电，在负载上得到的是半个正弦波。所以负载上输出的平均电压值为: ,12,, (5-1-1) U,2Usin(t)d(t),U,0.45UO222,0,,2 流过负载和二极管的平均电流为 UUO2II,,,0.45 (5-1-2) DORRLL (2)二极管截止时承受的最高反向电压就是整流变压器副边交流电压的最大值，即: u2 (5-1-3) U,U,2UDRM2M2 根据I和U就可以选择合适的整流二极管。为了使用安全，二极管的反向工作峰值电DDRM 压要选得比U大一倍左右 DRM 例5-1-1有一个单相半波整流电路，如图5-1-2(a)所示。已知负载电阻R=750Ω，变压器L副边电压U=20V，试求U、I，并选用二极管。 2oo 解: U,0.45U,0.45，20,9(V)O2 U9OI,,,0.012(A),12(mA)OR750 L I,I,12(mA)DO U,2U,2，20,28.2(V)DRM2 查半导体手册，二极管可选用2AP4，其最大整流电流为16mA，最高反向工作电压为50V。 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 3 5.1.2单相桥式整流电路 1、工作原理和输出波形 单相桥式整流电路如图5-1-3(a)所示。图中四只整流二极管VD、VD、VD、VD接成1234电桥形式，故称为桥式整流。图5-1-3(b)所示为单相桥式整流电路的一种简便画法。 a VD 4 VD1 + + + + + + RL RuL uuo u u1 2 uo 1 2 , , , , , , VD2 VD3 b (a) 原理电路(b) 简化画法 图5-1-3单相桥式整流电路 设整流变压器副边电压为:，当处于正半周时，其极性为上正下负，uu,2Usin(,t)222 即a点电位高于b点电位，整流二极管VD、VD正向偏置，处于导通状态，整流二极管VD、132VD反向偏置，处于截止状态。此时整流电路中的电流从a端开始，流经二极管VD至负载41R，然后经过二极管VD至b端，再经变压器,最后又回到a端形成回路，此时，负载R上L3L的输出电压，极性为上正下负。 u,u02 aa VDVD,41?++++++RR LuLuuuuuoo1212,,,,,,VD,VD2?3 bb 图5-1-4单相桥式整流电路 (a)正半周时电流的通路; (b)负半周时电流的通路 当处于负半周时，其极性为上负下正，即a点电位低于b点电位，整流二极管VD、u22 VD正向偏置，处于导通状态，整流二极管VD、VD反向偏置，处于截止状态。此时整流413 电路中的电流从b端开始，经二极管VD流经负载R，然后经过二极管VD至a端，再经变2L4压器,最后又回到b端形成回路，因此，负载R上也同样产生一个上正下负的输出电压，此L u,,u时，输出电压。其工作波形图和单相全波整流电路相同。 02 potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 4 u2 ωt 0π2π3π4π iD1 ωt 0π2π3π4π iD2 ωt 0π2π3π4π uo ωt 0π2π3π4π 图5-1-5 单相桥式整流电路的波形 由上可知，对于单相全波整流和单相桥式整流，无论电压是在正半周还是在负半周，u2 负载电阻R上都有相同方向的电流流过，负载电阻R得到的是单向脉动电压。 LL 2、参数计算 (1)输出平均电压为: ,122,, (5-1-4) U,2Usin(t)d(t),U,0.9UO222,0,, UUO2I(2)流过负载和二极管的电流平均值为:,,0.9 (5-1-5) ORRLL 桥式整流电路中，由于每只二极管只导通半个周期，所以流过每只二极管的平均电流都为负载电流的一半。即: U12II,,0.45 (5-1-6) DOR2L 每个二极管在截止时承受的最高反向电压为的最大值.即: u2 (5-1-7) U,U,2UDRM2M2 对几种整流电路进行比较。由表5-1-1可见，半被整流电路的输出电压相对较低。两管全波整流电路则需要变压器的副边绕组具有中心抽头，且两个整流二极管承受的最高反向电压相对较大。桥式整流电路输出电压高，整流二极管所承受的最高反向电压较低，同时因整流变压器在正负半周内部有电流供给负载，整流变压器效率较高。在同样的功率容量条件下，体积可以小一些。单相桥式整流电路的总体性能优于单相半波和全波整流电路，故广泛应用constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 5 于直流电源之中。 表5-1-1各种整流电路性能比较表 例5-1-2 试 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 一台输出电压为24V，输出电流为lA的直流电源，电路形式可采用半波整流或全波整流，试确定两种电路形式的变压器副边绕组的电压有效值，并选定相应的整流二极管。 解:(1)当采用半波整流电路时，变压器副边绕组电压有效值为: U24o(V) U,,,53.320.450.45 整流二极管承受的最高反向电压为: (V) U,2U,1.41，53.3,75.2DRM2 流过整流二极管的平均电流为: I,I,1A Do 因此可选用2CZ12B整流二极管，其最大整流电流为3A，最高反向工作电压为200V。 (2)当采用桥式整流电路时，变压器副边绕组电压有效值为: potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 6 U24o U,,,26.7(V)20.90.9 整流二极管承受的最高反向电压为: U,2U,1.41，26.7,37.6(V)DRM2 1流过整流二极管的平均电流为: I,I,0.5ADo2 因此可选用四只2CZ11A整流二极管，其最大整流电流为1A，最高反向工作电压为100V。 变压器副边电流有效值为: I,1.11I,1.11，1,1.11(A)20 变压器的容量为: S,UI,26.7，1.11,29.6(VA)22 5.2滤波电路 整流电路将交流电转换为直流电，但其中含有大量的交流成分，所以整流电路的后面必须接滤波电路，滤去交流成分，才可以得到比较平滑的输出电压。 滤波电路主要有电容滤波、电感滤波、复式滤波电路(包括LC型、CRC(π型)、CLC型滤波)等多种形式。 最简单的电容滤波电路是在整流电路的直流输出处与负载电阻R并联一电容器C，利用L 电容器的充放电作用，使输出电压趋于平滑，电容C起滤波作用。下面以单相半波整流电容滤波电路为例来说明。 1、工作原理 -2-1(a)所示。假设电路接通时恰恰在u单相半波整流电容滤波电路如图5由负到正过零的2时刻，这时二极管VD开始导通，电源u在向负载R供电的同时又对电容C充电。如果忽2L 略二极管正向压降，电容电压u紧随输入电压u按正弦规律上升至u的最大值。然后u继C222续按正弦规律下降，且，使二极管VD截止，而电容C则对负载电阻R按指数规律放u,uL2C 电。u降至u大于u时，二极管又导通，电容C再次充电……。这样循环下去，u周期性C2C2变化，电容C周而复始地进行充电和放电，使输出电压脉动减小，如图5-2-1(b)所示。电容C放电的快慢取决于时间常数(,,RC)的大小，时间常数越大，电容C放电越慢，输出电压L u就越平坦，平均值也越高。 uo2 VD ωt 0π2π3π4π + + + + RLC uu1 2 uo uo , , , constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneouωt π2π3π4π0 7 (a) 电路 (b) 波形 图5-2-1 单相半波整流电容滤波电路及其输出电压波形 单相桥式整流、电容滤波电路的输出电压波形如图5-2-2所示。 图5-2-2单相桥式整流、电容滤波电路的输出电压波形 单相桥式整流、电容滤波电路的输出特性曲线如图5-2-3所示。从图中可见，电容滤波电路的输出电压在负载变化时波动较大，说明它的带负载能力较差，只适用于负载较轻且变化不大的场合。 Uo 1.4Uo 0.9Uo 0 Io 图5-2-3单相桥式整流、电容滤波电路的输出特性曲线 2、电容滤波的计算 —般常用如下经验公式估算电容滤波时的输出电压平均值。 半波: (5-2-1) U,Uo2 全波: (5-2-2) U,1.2Uo2 1 为了获得较平滑的输出电压，一般要求，即: R,(10~15)L,C T (3~5),,RC,L2 式中T为交流电压的周期。滤波电容C一般选择体积小，容量大的电解电容器。应注意，普通电解电容器有正、负极性，使用时正极必须接高电位端，如果接反会造成电解电容器的损坏。 加入滤波电容以后，二极管导通时间缩短，且在短时间内承受较大的冲击电流()，i，iCo为了保证二极管的安全，选管时应放宽裕量。 单相半波整流、电容滤波电路中，二极管承受的反向电压为u,u，u，当负载开路时，DRC2承受的反向电压为最高，为: (5-2-3) U,22UDRM2 potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 8 因为滤波电容是隔直通交，它的平均电流为零，故二极管的平均电流仍为负载电流的一半，但由于二极管导通时间缩短，故流过二极管的冲击电流较大。所以在选择二极管时应留有充分的电流余量，通常按平均电流的2~3倍选择二极管。 例5-2-1设计一单相桥式整流、电容滤波电路，要求输出电压U=36V，已知负载电阻0 R=100Ω，交流电源频率为f=50Hz，试计算整流二极管的平均电流、最高反向电压和滤波电L 容器。 解:(1)流过二极管的平均电流: U111360 I,I,,,,,0.18A,180(mA)D0222100RL 变压器副边电压有效值: U360U,,,30(V) 21.21.2 整流二极管承受的最高反向电压: U,2U,1.41，30,42.3(V)DRM2 因此可选择2CZ11B作整流二极管，其最大整流电流为1A，最高反向工作电压为200V。 (2)滤波电容 T,5，,放电时间常数:选择 2 T11，则: ,,RC,5，,5，,5，,0.05sL22f2，50 0.05,,6C,,,500，10F,500(uF) R100L 5.3 直流稳压电路 将不稳定的直流电压变换成稳定且可调的直流电压的电路称为直流稳压电路。 直流稳压电路按调整器件的工作状态可分为线性稳压电路和开关稳压电路两大类。前者使用起来简单易行，但转换效率低，体积大;后者体积小，转换效率高，但控制电路较复杂。随着自关断电力电子器件和电力集成电路的迅速发展，开关电源已得到越来越广泛的应用。 5.3.1并联型直流稳压电路 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 9 工作原理:输入电压U波动时会引起输出电压U波动。如U升高将引起U=U随之升ioioZ高，导致稳压管的电流I急剧增加，使得电阻R上的电流I和电压U迅速增大，U的增大ZRR抵消了U增加，从而使U基本上保持不变。 io U??U??I??I??U? i0ZRR ? Uo 反之，当U减小时，U相应减小，仍可保持Uo基本不变。 iR 当负载电流I发生变化引起输出电压U发生变化时，同样会引起I的相应变化，使得ooZU保持基本稳定。如当I增大时，I和U均会随之增大使得U下降，这将导致I急剧减小，ooRoZ使I仍维持原有数值保持U不变，使得U得到稳定。 Ro + U,I R IoRI++Z+ RLUDUiZUoZ, ,, 图5-3-1并联型直流稳压电路 可见，这种稳压电路中稳压管VD起着自动调节作用，电阻R一方面保证稳压管的工作Z 电流不超过最大稳定电流I，另一方面还起到电压补偿作用。 ZM 5.3.2串联型直流稳压电路 V1 ,IoRUR+4RBE113+R a+VRR2P+LUUiUo BE2 +,,R+bUFRU 2,Z, , 图5-3-2 串联型直流稳压电路 串联型直流稳压电路由采样单元、基准单元、比较放大单元、调整单元4个部分组成。 (1)采样单元。由R、R、R组成的分压电路构成，它将输出电压U分出一部分作为取1P2o样电压U，送到比较放大环节。 F (2)基准单元。由稳压二极管VD和电阻R构成的稳压电路组成，它为电路提供一个稳定Z3 的基准电压U，作为调整、比较的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 。 Z 设V发射结电压U可忽略，则: 2BE2 RbU,U,U FZoR，Rab 或: potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 10 RR，abUU, oZRb 用电位器R即可调节输出电压U的大小，但U必定大于或等于U。 PooZ (3)比较放大单元。由V和R构成的直流放大器组成，其作用是将取样电压U与基准电24F压U之差放大后去控制调整管V。 Z1 (4)调整单元。由工作在线性放大区的功率管V组成，V的基极电流I受比较放大电路llB1输出的控制，它的改变又可使集电极电流I和集、射电压U改变，从而达到自动调整稳定C1CEl 输出电压的目的。 当电网电压波动时，若电网电压升高，引起输出电压U增加时，取样电压U相应增大，0F使V管的基极电流I和集电极电流I随之增加，V管的集电极电位U下降，因此V管2B2C22C2l的基极电流I下降，I下降，U增加，U下降，从而使U保持基本稳定。 B1C1CE100 这一自动调压过程可表示如下 U??U??U??U??I??I??U??U??I??U??U? ioFBE2B2C2CE2BE1B1CE1o 若电网电压下降，串联型稳压电路的自动稳压过程则与上述过程相反。 当负载变动时，若负载电阻减小，串联型稳压电路的自动稳压过程为 R??U??U??U??I??I??U??U??I??U??U? LoFBE2B2C2CE2BE1B1CE1o 若负载电阻增大，串联型稳压电路的自动稳压过程则与上述过程相反。 【巩固练习】 习 题 五 5-1 设一半波整流电路和一桥式整流电路的输出电压平均值和所带负载大小完全相同，试问两个整流电路中整流二极管的电流平均值和最高反向电压是否相同, 5-2如果要求某一单相桥式整流电路的输出直流电压为36V，直流电流为1.5A，试选择合适的二极管。 5-3欲得到输出直流电压U=50V，直流电流I=160mA的电源，问应采用哪种整流电路,0 0 画出电路图，并计算电源变压器的容量(计算U和I)，选定相应的整流二极管(计算二极22 管的平均电流I和承受的最高反向电压U)。 DDRM 5-4 在图5-1所示电路中，已知R=8KΩ，直流电压表V的读数为110V，二极管的正向L2 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 11 压降忽略不计，求: (1)直流电流表A的读数;(2)整流电流的最大值;(2)交流电压表V的读数。 1 图5-1 习题5-4的图 图5-2 习题5-5的图 5-5图5-2所示电路为单相全波整流电路。已知U=10V，R=100Ω。 2L (1)求负载电阻R上的电压平均值U与电流平均值I，在图中标出u、i的实际方向。 L0000 (2)如果VD脱焊，U、I各为多少, 200 (3)如果VD接反，会出现什么情况, 2 (4)如果在输出端并接一滤波电解电容，试将它按正确极性画在电路图上，此时输出电压U约为多少 0 5-6单相桥式整流、电容滤波电路，已知交流电流f=50Hz，要求输出直流电压和输出直流电流分别为U=30V，I=150mA，试选择二极管及滤波电容 00 5-7在图5-3所示桥式整流电容滤波电路中，U=20V，R=40Ω，C=1000uF，试问: 2L (1)正常时U为多大, 0 (2)如果电路中有一个二极管开路， U又为多大, 0 (3)如果测得U为下列数值，可能出现了什么故障,?U=18 V:?U=28 V:?U=9 V。 0000 图5-3 习题5-7的图 图5-4 习题5-8的图 5-8 图5-4所示桥式整流电路，设V，试分别画出下列输出电压u的波u,2Usin(,t)AB22 形。 (1) S、S、S打开，S闭合; 1234 (2)S、S闭合，S、S打开; 1234 (3)S、S闭合、S、S打开; 1424 (4) S、S闭合、S、S打开; 2413 potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 12 (5) S、S、S闭合，S打开; 1243 (6) S、S、S、S全部闭合。 1234 自测题五 1、单相半波整流脉动直流电压平均值为 A、0.45U B、0.9U C、U D、1.2U 22222.、单相桥式整流脉动直流电压平均值为 A、0.45U B、0.9U C、U D、1.2U 22 223.、单相桥式整流电容滤波时的输出电压平均值为 A、0.45U B、0.9U C、U D、1.2U 22 224.、单相半波整流电容滤波时的输出电压平均值为 A、0.45U B、0.9U C、U D、1.2U 22 22、直流稳压电源一般由哪一种组成, 5 A、整流电路、滤波电路、稳压电路、贮能电路 B、电源变压器、滤波电路、贮能电路、稳压电路 C、滤波电路、整流电路、贮能电路、电源变压器 D、电源变压器、整流电路、滤波电路、稳压电路 6、在通常情况下，改变串联型稳压电源的输出幅度是通过调整哪个来实现的 A、调整管的放大倍数 B、比较放大器的放大倍数 C、取样电路中的电位器 D、基准电路的稳压值 7、在串联型稳压电路中，取样电路电阻器的温度系数越小，其输出电压受温度的影响 A、越小 B、越大 C、成正比增大 D、与温度系数无关 8、利用半导体的什么特性可实现整流 A、双向导电 B、稳压 C、贮能 D、单向导电 9、利用电抗元件的什么特性实现滤波 A、单向导电 B、贮能 C、变频 D、电压不能突变 10、串联型直流稳压电路的调整管必须工作在什么状态 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 13 A、导通 B、饱和 C、放大 D、开关 11、单相半波整流电容滤波电路，输出的电压波形是 A、锯齿波 B、尖脉冲 C、脉动直流电 D、正弦交流电 12、用于整流的二极管型号是 A、2AP9 B、2CW14C C、2CZ52B D、2CK84A 【实践项目】 项目7串联稳压电源的安装与测试 一、学习任务 最终目标: 掌握串联稳压电源的安装和调试 促成目标: 1、了解单相桥式整流、电容滤波电路的特性 、掌握串联型稳压电源主要技术指标的测试方法 2 3、掌握元件参数的选择方法 二、相关知识 图1是由分立元件组成的串联型稳压电源的电路图。T为变压器，把220V的正弦电压R变化为12V的正弦电压，D,D组成桥式整流电路，C为滤波电容，U=1.2U。T、T组141C1212 成的复合管为调整管，R和D为基准电压，R、R、R为取样网络,T为比较放大电路。 3Z12W3 图1 稳压电源的主要性能指标 1、输出电压U和输出电压调节范围 0 R，R，R1P2 调节R可以改变输出电压U。 U,,(U，U)W00ZBE3R，R2P 2、输出电阻r o 输出电阻r定义为，当输入电压U(稳压电路输入)保持不变，由于负载变化而引起的oa potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 14 输出电压变化量与输出电流变化量,I之比，即 o ,U0r,| 0U,常数a,I0 3、稳压系数S(电压调整率) 稳压系数定义为，当负载保持不变，输出电压相对变化量与输入电压相对变化量之比， ,U/U00S|即: ,R,常数L,U/U11 由于工程上常把电网电压波动?10,作为极限条件，因此也有将此时输出电压的相对变化,U/U作为衡量指标，称为电压调整率。 oo 三、预习与思考 1、焊接注意事项 2、输出电压U的计算方法 0 3、当电压上升时稳压过程 4、当负载增加时稳压过程 5、接上负载R与不接负载R,电压变化是否明显? LL 6、D断路;短路;接反时输出电压变化情况, Z 7、在桥式整流电路中，能否用双踪示波器同时观察u和u波形，为什么, 2L 8、在桥式整流电路中，如果某个二极管发生开路、短路或反接三种情况，将会出现什么问题, 9、怎样提高稳压电源的性能指标(减小S和r), o 四、项目设备 名 称 数 量 备 注 双踪示波器 1 电子管毫伏表 1 直流电压表、毫安表 1 数字万用表 1 电路板、电烙铁、变压器、二极管、电解电容、电阻、三极管等 五、项目实施 组织形式:5人为一小组，推选一位组长。 1、安装焊接步骤和方法 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 15 安装桥式整流电路的四个整流二极管,注意二极管的正负极,焊接好的四个二极管高度一样,宽度一样,管脚弯曲成直角。 ? 焊接滤波电容C,注意电容的正负极千万不能焊反,否则电容会爆炸。 1 ? 焊接调整管T、T和电阻R ,注意三极管e、b、c的三个管脚不能焊错。 124 ? 焊接电阻R与D。 3Z ? 焊接取样网络R、R、R电阻 1W2 ? 焊接三极管T注意三极管e、b、c的三个管脚不能焊错。 3 ? 焊接R L ? 把电路板翻过来,在反面按图准备好连接的电线,并且逐步逐点地焊好,焊好的连接线一定要直,不能弯曲。 ? 正、反面都焊好后先自己检查一遍,相互检查一遍，然后再请老师检查,确实没有错误经老师同意后再通电,测量输出电压并作 记录 混凝土 养护记录下载土方回填监理旁站记录免费下载集备记录下载集备记录下载集备记录下载 。 图2实物焊接电路参考图(电路版正面) 图3实物焊接电路参考图(电路版反面) potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 16 2、调试 串联型稳压电源的调试采用逐级调试的方法,先断开电路板反面焊好的连接线,然后准备调试。 ?仅调试变压级:用万用表交流档50V测试变压器的输出电压U值,注意万用表的档位2 一定要在交流电压档。 U= V 2 ?接上四个整流二极管的连接线,用万用表直流电压档50V,测量桥式整流的电压。注意万用表的档位一定要在直流电压档。 U= 理论值=0.9U 02 ?接上滤波电容的连接线,用万用表直流电压档测量电容两端的电压 U= 理论值=1.4U 02 ?焊接上R与T，T的连接线,测量输出电压U, 即T的发射极与地之间的电压。 41201 U= 理论值=1.4U,0.3 02 ?焊接上R与D的连接线,测稳压二极管两端的基准电压U 3ZZ U= Z ?焊接R、Rw、R的连接线,把万用表红表棒接在Rw中间触点位置,黑笔杆接地,用直12 流电压档测量电压,改变Rw位置,测量中间触点与地之间的电压,最上端Uw= _____，最下端Uw=______。 ?接上T的连接线,测量输出电压U 30 调节Rw测量输出电压:Rw最上端U= Rw最下端U= 00 ?接上负载R的连接线，测量输出电压U L0 调节Rw测量输出电压:Rw最上端U= Rw最下端U= 00 3、串联型稳压电源故障排除 ?电源变压器损坏或引脚没有焊好，故障现象，变压器次级无交流电压U或桥式整流电2路交流电压输入端无交流电压U 2 ?一个整流二极管断路或没有焊好，故障现象,由全波整流变成半波整流,输出电压会降低，有电容滤波时电压由1.2U变成1.0U，无电容滤波时电压由0.9U变成0.45U 2222 ?有一个二极管接反,或有一个二极管短路，故障现象，变压器发热，无输出电压，因为变压器次级输出电压被短路。 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 17 ?如果滤波电容失效或没有焊好。故障现象，输出电压降低，交流成份变大,电压由1.2U2下降到0.9U左右。 2 ?如果滤波电容漏电。故障现象:电容发热,输出电压降低。 ?R断路,不能给T、T提供偏置电压，使T、T处于截止状态，故障现象U=0。 412120 ?R断路，应该不能使稳压二极管处于反向击穿状态，无基准电压，但是，输出电压通3 过T发射极使稳压管处于临界击穿状态、输出电压变化不大。 3 ?R、R、R断路，无取样网络，其中R断路，T处于截止状态，U最大;R断路，12W1202T处于饱和状态，U最小;Rw中间触点没有焊好,T载止，T饱和U最大。 20210 ?D断路U最大,D短路U最小 Z0Z0 ?T损坏，T发射极与集电极短路，U最小;T发射极与集电极断路，U最大;T、,33003T损坏，T与T断路，U,0;T与T短路，U为最大。 2120120 4、串联型稳压电路性能测试 ?U接220V交流电源，调节R，观察空载时输出电压U是否随着改变。若U不随着1Woo改变，则说明稳压电路没有工作。因为稳压电路是一个深负反馈的闭环系统，只要环路中任一个环节出现故障(某管截止或饱和)，稳压电路就会失去自动调节作用。此时可分别检查基准电压U，输入电压U，输出电压U，以及比较放大器和调整管各电极的电位(主要是UZ1oBEQ和U)，分析它们的工作状态是否都处在线性区，从而找出不能正常工作的原因，排除故CEQ 障以后就可以进行下一步测试。 ?测量输出电压可调范围 取U=220V，调节电位器R，测量输出电压的最大值U和最小值U以及对应稳压电1WOHOL路中调整管T的管压降U，记入表1中 1CE1 表1 U UOL UCE1L UOH UCE1H 1 ?测量各级静态工作点 取U=220V，调节U=12V;I=100mA，测量各级静态工作点，记入表2中。 1oo 表2 TTT1 2 3 U(V) B U(V) C U(V) E potassium hydrogeng of at a temperature of 110 of the dry to constant weight in the oven and placed in dry cooling. Weighing after drying and coolin . 4, the analysis step calibration of standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagentplate. Dry: desiccant and has effectively adequate within a perforated metal ?temperature oven: temperature controlled at 110 ? 1 250m1 ... Basic glassware: volume 25m1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constantolume in. Phenolphthalein indicator solution: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: val grade reagent and distilled water. Standard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plaalytices to the acidity of not more than 12mL samples of starch and its derivatives. 2, reagent: determination process, only use any titration with sodium hydroxide standard solution until neutral consumption volume of the standard solution. This law appliion bL0g 0.lmol/L standard sodium hydroxide solution consumed by the sample to represent the number of ml. Principle: starch emulsacidity of starches: starch and its derivatives and emulsion standard sodium hydroxide solution consumed by the sample size. s: theis value should be no more than an average result of 0.2%. Determination of acidity of starches and definitions and principlel simultaneously or in quick succession for the second determination, the absolute value of the difference of the results. Tharithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personne 18 ?U=220V，U=12V，R=120Ω，改变变压器原边电压使U为242V和198V(即模拟电1oL1 源电压波动?10,)分别测出输出直流电压U，记入表3。 o ?测量输出电阻r o 取U=12V，I=100mA，改变滑线变阻器位置，使I=50mA和0测量相应的U值，记入oooo表4中。 表3 RL=120Ω 表4 测试值 计算值 测试值 计算值 (mV) U(V) rIooo U(V) U(V) U(V) 12o 50 r = 012198 100 12 220 12 0 r = 023242 六、项目 报告 软件系统测试报告下载sgs报告如何下载关于路面塌陷情况报告535n,sgs报告怎么下载竣工报告下载 1、根据表3表和表4所测数据，计算稳压电路的稳压系数S和输出电阻r，并进行分析。 o 2、分析项目中出现的异常现象。 七、项目评价 评分表 主考,,,,得分______ 考核内容 配分 评分标准 扣分 得分 1、不按图装接，扣5分 按图装接 2、不会用仪器、仪表选择元件，扣2分 20 3、元件极性接反或损坏，每只扣2分 1、不合理、不美观、不整齐，扣5分 2、焊接点有虚焊、假焊，每点扣2分 元件安装和焊接 30 3、焊点有毛刺、不光滑，每点扣2分 4、敷线不平直、不合理，每根扣2分 1、电路原理及元件作用不清楚，扣2分。 通电试验 2、、通电试验不成功，扣2分。 20 3、故障排除不成功，扣2分。 电路性能测试 电路性能测试5项，缺1项，扣5分。 30 constant weight in the oven and placed in dry cooling. Weighing after drying and cooling of potassium hydrogen standard solution of sodium hydroxide to potassium hydrogen phthalate reference reagent at a temperature of 110 of the dry ton of . Dry: desiccant and has effectively adequate within a perforated metal plate. 4, the analysis step calibratio?ed at 110 ? 1 ... Carbonate titration tube: 50ral ... Analytical balance. Magnetic stirrer. Constant temperature oven: temperature controll e 25m1: 1g phenolphthalein in ethanol soluble in lOOmL, 95%. 3, equipment Erlenmeyer flask: volume 250m1 ... Basic glassware: volumStandard solution of sodium hydroxide: 0.1mol/L. Potassium hydrogen phthalate: base plain. Phenolphthalein indicator solutionater. L samples of starch and its derivatives. 2, reagent: determination process, only use analytical grade reagent and distilled wdard solution until neutral consumption volume of the standard solution. This law applies to the acidity of not more than 12me stane solution consumed by the sample to represent the number of ml. Principle: starch emulsion by titration with sodium hydroxiderivatives and emulsion standard sodium hydroxide solution consumed by the sample size. L0g 0.lmol/L standard sodium hydroxidits d rage result of 0.2%. Determination of acidity of starches and definitions and principles: the acidity of starches: starch andn for the second determination, the absolute value of the difference of the results. This value should be no more than an avesly or in quick successioarithmetic mean of the second determination as a result. Results one decimal. 5, allows the analysis of personnel simultaneou 19