Measurement of resistance, capacitance, voltage and current

　　1. Experimental Purpose
　　1. Understand the use of power supply, measuring instruments and digital multimeter;
　　2. Master the methods of measuring resistance, capacitance, voltage and current;
　　3. Understand the influence of measuring instrument range, resolution and accuracy on measurement results.

　　2. Principle Description
　　For the measurement principles and methods of resistance, capacitance, voltage and current, please refer to Sections 3.2 and 3.3 of Chapter 3. For the calculation method of digital meter measurement error, please refer to Section 4.1.2 of Chapter 4.

　　3. Experimental tasks
　　1. Carefully read the manuals of the laboratory experimental devices and instruments, and fill in the technical performance of the digital multimeter, DC power supply, and digital DC voltage/current meter used in this experiment in Tables 6.1.1 to 6.1.3 respectively.

Table 6.1.1 Technical characteristics of _________ type multimeter

Table 6.1.2 DC power supply technical performance

Table 6.1.3 Technical performance of digital DC meter

　　2. Use a digital multimeter to measure:

　　(1) When the indicated values ​​of the precision adjustable resistor are 2, 10, 50, 200, 1000, and 9999, the measured data shall be filled in Table 6.1.4;
　　(2) When the measured data of the resistance value on the DG08 experimental assembly is filled in Table 6.1.5;
　　(3) When the measured data of the capacitance value on the DG08 experimental assembly is filled in Table 6.1.6.

Table 6.1.4 Digital multimeter measuring precision adjustable resistance

Table 6.1.5 DG08 resistance measured by digital multimeter

Table 6.1.6 DG08 capacitance measured by digital multimeter

　　3. Use a digital multimeter and a digital DC meter to measure the DC voltage and current respectively.

　　(1) Connect according to Figure 6.1.1, where Us≈15V, which is a DC regulated power supply; R1 and R2 are precision adjustable resistors, with a nominal value of 510 for R1 and 1K for R2. Use a digital multimeter and a digital DC voltmeter to measure US, U1 and U2 respectively, and fill in the measured data in Table 6.1.7.

Figure 6.1.1 Figure 6.1.2

Table 6.1.7 DC voltage measurement

　　(2) Connect according to Figure 6.1.2, where IS ≈ 20mA, which is a DC current-stabilized power supply, and R1 and R2 are precision adjustable resistors. Use a DC ammeter and a DC microammeter to measure IS, I1, and I2 in the following two cases, respectively, and fill in the measured data in Table 6.1.8.
　　(a) The nominal values ​​of R1 and R2 are both 10;
　　(b) The nominal values ​​of R1 and R2 are both 1K.

Table 6.1.8(a) DC current measured with a DC ammeter

Table 6.1.8(b) DC current measured with a DC microammeter

　　4. Experimental instruments and equipment
　　1. Digital multimeter
　　2. Electrical comprehensive experimental table
　　3. DG08 dynamic component experimental assembly

　　V. Pre-study thinking and precautions
　　1. What preparations should be done before entering the laboratory and starting the experiment?
　　2. Before wiring, where should the power switch of the laboratory bench and the output adjustment knob of the DC power supply be placed? What should be the range of the meter and the indication value of the resistance box?　　

　　3. After the experiment, you should first turn off the voltage (current) power switch, then turn off the power switch of the experimental bench, and then remove the wires.
　　4. When measuring, the conversion switch of the multimeter should be set to the required measurement function and range. If the size of the measured value cannot be estimated in advance, the conversion switch should be set to the highest range first, and then gradually reduced to the appropriate position.
　　5. In order to improve the measurement accuracy and reduce the measurement error of the measured value, how should the measurement range of the multimeter be selected? Give an example.
　　6. Before measuring capacitance with a multimeter, the capacitor should be completely discharged. At a small range, due to the influence of distributed capacitance such as the test lead, there will be a small reading when the test lead is open. This is normal and will not affect the measurement accuracy.
　　7. In experimental task 3, when measuring DC current, why should it be measured separately in two situations? What phenomenon will occur? Please explain.
　　8. If the ammeter does not have a normal reading in the experiment, what may be the reason? How to check?

　　VI. Experimental report requirements
　　1. Complete the experiment according to the experimental task and fill in the experimental data into the corresponding table;
　　2. Analyze the experimental results and discuss the causes of each experimental error;
　　3. Calculate the instrument error when measuring resistance and capacitance.