LK-00 AC DC Circuit Board and How to use Multimeter - rev2

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Dec 6, 2023

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LK-00 AC/DC Electronics Lab and How to use Multimeter Rev 6-2022 by AQ Objective 1. Recognize Pasco lab kit equipments 2. Learn how to use the Circuit Board 3. Learn how to use mulitimeter Equipment 1. EM-8656 AD/DC Electronics Lab 2. PS-3211 Wireless voltage sensor 3. PS-3212 Wireless current sensor 4. SE-8829 Student Multimeter 5. 2 Batteries 6. Wires, Resistors, and Capacitors Multimeter Structure of the AC/DC Circuit Board: The structure of the Circuit Board (EM-8656 AD/DC Electronics Lab) as shown in the Figure 1. We define the names of each spring connector in the circuit board as shown in the figure. In the rectangular areas of Figure 1, the springs are connected in pairs, oriented perpendicular to each other and named C and S. In a given rectangular area, the two springs should be treated equally in circuit connection. For example, connecting to C1 means connecting to S1 also. Therefore the names C1 and S1 are interchangeable in the following circuit build procedures. Similarly for C2 and S2, and the others. 1 Circuit Board (EM-8656 AD/DC Electronics Lab) Wireless Current sensor Wireless voltage sensor

Figure 1: definition of the names of each spring connector So S1 and C1 are essentially the same point, but S1 and S2 (and the rest) are not connected together – we will make these connections in our circuit. The way the connection are made is: take the wire and push it in-between the coils of the springs in such a way that the wire protrudes on both sides. See Fig. 2. This ensures that the wire is touching the spring at four points, which makes a good connection. Figure 2: How to attach wires to springs Learn how to use multimeter : 1. Continuity Test: 2

1.1. A multimeter has the Continuity Test mode ( ). 1.2. Continuity is the presence of a complete path for current flow. A circuit is complete when its switch is closed. 1.3. A digital multimeter’s Continuity Test mode can be used to test switches, fuses, electrical connections, conductors and other components. A good fuse, for example, should have continuity. 1.4. A multimeter emits an audible response (a beep) when it detects a complete path. 1.5. The beep, an audible indicator, permits technicians to focus on testing procedures without looking at the multimeter display. 1.6. When testing for continuity, a multimeter beeps based on the resistance of the component being tested. That resistance is determined by the range setting of the multimeter. Examples: 1.7. If the range is set to 400.0 Ω, a multimeter typically beeps if the component has a resistance of 40 Ω or less. 1.8. If the range is set 4.00 kΩ, a multimeter typically beeps if the component has a resistance of 200 Ω or less. 1.9. The lowest range setting should be used when testing circuit components that should have low-resistance value such as electrical connections or switch contacts. 2. Resistance Measurement: 1. Coding on the Resistor : Resistors are color coded to indicate their value. The color coding can be seen in Figure 3, where each color represents a number. To read the color coding, note the colors of the four bands. The first and second numbers (i.e. colors) are the first and second digits of the resistance value. The third number (color) is the multiplier in power of ten. The fourth color is the tolerance (or error) in the value of the resistance. As an example, a resistor colors are: Orange-Yellow-Red-Gold. The color coding shows Orange and Yellow to be 3 and 4, which makes it 34. The Red is 2, which means 10 2 . The resistance is then 34x10 2 ohms. Gold indicates that this value is within ±5% of its actual resistance. Similarly: Blue-Red-Green-Silver becomes 62x10 5 ohms ± 10%. Figure 3: Resistance Color Coding Chart c 2. Measure resistance when components are not connected in a circuit: It is always advisable not to measure the resistance of an item that is in a circuit. It is always best to make the measurement of the component on its own out of the circuit. If a measurement is made in-circuit, then all the other components around it will have an effect. Any other paths that will allow current to pass will affect the readings, making them inaccurate to some degree. 3

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3. Remember to ensure the circuit under test is not powered on: Under some circumstances it is necessary to measure resistance values actually on a circuit. When doing this it is very important to ensure the circuit is not powered on . Not only will any current flowing in the circuit invalidate any readings, but should the voltage be high enough, the current resulting could damage the multimeter. 4. Leakage path through fingers can alter readings in some cases. When making some resistance measurements it is necessary to hold a resistor or component onto the multimeter test probes. If high resistance measurements are being made the leakage path through the fingers can become noticeable. 5. Select the required range: The digital multimeter needs on and the required range selected. The range selected should be such that the best reading can be obtained. Normally the multimeter function switch will be labelled with the maximum resistance reading. Choose the one where the estimated value of resistance will be under but close to the maximum of the range. In this way the most accurate resistance measurement can be made. 6. Make the measurement: With the multimeter ready to make the measurement the probes can be applied to the item that needs to be measured. The range can be adjusted if necessary. 7. Turn off the multimeter: Once the resistance measurement has been made, the multimeter can be turned off to preserve the batteries. It is also wise to turn the function switch to a high voltage range. In this way if the multimeter is used to again for another type of reading then no damage will be caused if it is inadvertently used without selecting the correct range and function. 2. Voltage Measurement: Voltage measurements look at the potential difference between two points. Procedures of voltage measurement with a multimeter: 3.1 Before current measurement, check the whether the multimeter’s socket is correct. 3.2 At the beginning the measurement, use maximum range to protect the meter. If needed reduce the range gradually. 3.3 Switch the multimeter to the voltage ranges. It is best to select a range higher than the expected voltage so that there is no chance of the meter being overloaded and damaged. 3.4 Check that the test leads are plugged into the correct sockets. Many multimeters have different sockets for different types of measurement so it is worth checking the correct ones have been chosen before making the measurement. Usually a meter will be provided with two leads, one black, and the other red. The black one is normally taken as the negative one. It is connected to the negative or "common" socket on the meter. The red one is connected to the positive socket. 3.5 When making the measurement, the positive lead should be connected to terminal which is expected to have the higher electric potential. If the leads are connected the wrong way round a negative voltage will be displayed. 3.6 With the multimeter connected, power can be applied to the circuit. The multimeter switches can then be changed to reduce the value of the range. This is done until the greatest number of significant digits can be read on the meter. In this way the most accurate reading is obtained. 4

3. Current Measurement: 1. Current measurement requires that the circuit in which the current is flowing has to be broken and the multimeter inserted into the circuit. 2. In order that the multimeter does not alter the operation of the circuit when it is used to measure current, the resistance of the meter must be as low as possible. Therefore resistances of meters used to measure current are normally very low. 3. Before current measurement, check the circuit loop is not short (circuit has at least one resistor). And multimeter socket is correct. At the beginning the measurement, use maximum range or socket first. If needed reduce the range or socket. When the measurement finished, return to the meter’s original setting. 4. Insert the probes into the correct connections. Often one labelled common into which the black probe is normally placed. The other probe should be entered into the correct socket for the current measurement to be made. 5. Set main selector switch on the meter switch to the correct measurement type, (i.e. DC current) and range for the measurement to be made. 6. When the measuring the current, optimize the range for the best reading. If possible enable all the leading digits to not read zero, and in this way the greatest number of significant digits can be read. 7. Once the reading is complete, it is a wise precaution to place the probes into the voltage measurement sockets and turn the range to maximum voltage. This will prevent the meter from damage if the meter is accidentally connected without thought. PROCEDURE Resistance Measurements 5.1 Select 4 resistors of different values. Do not select any resistor of less than 100 ohms. Note their colors and coded values in Table 1. 5.2 Attach one resistor at a time between the springs C3 and C7. Measure their resistance and note in Table 1. 5.3 Calculate and note the percent difference in the measured and coded values. Battery Voltage 5.4 Attach on D-Cell in the top Battery Holder (i.e. between B3 and B4), keeping the positive side towards B4. 5.5 Set the Multimeter to DC Voltage, with a range around 5 volts. Connect one prong of the Multimeter to B4 and the other to B3. Note the voltage of the battery. Voltage Across Resistors 5.6 Take some wires and connect: B4 to SW1 (one end of the Push-Button Switch). Connect SW2 (the other end of the Push Button Switch) to S3. Connect S7 to S6. Connect S6 to B3. Connect one resistor between C3 and C7. 5

5.7 When you press the Push Button Switch, the circuit will be complete, and current will flow from positive of the battery to B4– to the Switch – to S3 / C3 – through the resistor to C7 / S7 – to S6 – to B3 – to the negative of the battery. 5.8 Set the Multimeter to read DC voltage, range about 5 volts. Connect one of its prongs to S3 and other to S7. Now press the Switch and note the reading of the voltage across the resistance. Repeat with four other resistances. And note the values in table 1. Current Through Resistors 5.9 Now remove the Multimeter. Set it on DC Current. Select the highest value of current as the range. Remove the wire between S7 and S6, and connect the two prongs of the Multimeter in between these two (S6 and S7). Now the Multimeter is in series with the circuit, and ALL current through the resistor will also flow through it. 5.10 Press the Switch and note the value of the current. If you do not get a value, reduce the range on the ammeter and measure current. (Always start with the highest range. The ammeter can easily be damaged by a current that is beyond its selected range). Using Wireless Sensors for Voltage and Current 5.11 Take out the Multimeter and connect the Wireless Current Sensor in its place. 5.12 Turn on Capstone Software. Turn on the Wireless Voltage Sensor and Wireless Current Sensor. Click Hardware Setup. Capstone will start detecting the Sensors. Select them when Capstone detects them. Make sure the numbers match. Click Hardware Setup again to close it. 5.13 On Capstone, select voltage and current How???? 5.14 Connect one prong of the Voltage Sensor to S3 and the other to S7. 5.15 Press the Switch. You should now see values of current and voltage in Capstone. 5.16 When values stabilize, note them. 5.17 Repeat measurements with the same resistors as before. 6

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REPORT FORM DATA Table 1: Resistances No Color codes Resistor Value from Color Codes Measured Value of Resistance Percent Error in Resistance Table 2: Voltages and Currents. Battery Voltage from step 5.5: ____________ No By Using Multimeter By Using Wireless Sensors Measured Voltage Across Resistor Measured Current Across Resistor Measured Voltage Across Resistor Measured Current Across Resistor 7

Reference : https://www.youtube.com/watch?v=bF3OyQ3HwfU https://www.electronics-notes.com/ REPORT SUBMISSION: Submit the following in the Lab-2 Online Lab Activity during Lab time: Show During Lab Time Points 1. Use your camera to show your setup for Resistance Measurement. 5 2. Use your camera to show your setup for Current Measurement using Multimeter. 5 3. Share your screen to show measurement being made by Capstone. 5 Report 4. Tables 1 and 2 20 5. At least four pictures, one for each type of measurement 4*5 = 20 6. Discussion / Conclusion / What you learnt from this Lab 10 total 65 8

LK-00 AC DC Circuit Board and How to use Multimeter - rev2

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