3. Using your observations of the different dielectrics, explain the effect of dielectric on the capacitance. What purpose do you think a dielectric might serve? [5 pts] Part 2: Capacitors in parallel We can create complex circuits by connecting multiple capacitors to a single battery. Capacitors in parallel are connected such that each capacitor has its own independent connection to the battery. . Click on the Multiple Capacitors tab at the top of the simulation. . From the right side menus under Meters, check the boxes for Total Capacitance and Voltmeter. . Under Circuits you will see several options. Select 2 in parallel. . The simulator will construct Circuit 1 shown in Fig 3.2, two capacitors in parallel. . Use the slider by the capacitor to set Capacitor A to 1.00x10 18F and and Capacitor B to 2.00X10-13 F. B B Circuit # 1 Circuit # 2 Fig. 3.2: Capacitors in parallel 4. Set the battery voltage to 1.5V to turn it on. Use the voltmeter to measure the voltage across each capacitor. Record the absolute value of V across each capacitor. [5 pts] AVbattery = 1.5V, AVA = , AVB = 5. Using the set capacitance of each capacitor (CA = 1.0x10-13F, CB = 2.0x10-13 F), calculate the charge on each capacitor using the equation 3.1. [5 pts] Capacitor A Capacitor B 31. Slide the battery voltage to +1.5 V. This will turn on the battery and cause the capacitor to charge. . Use the green colored arrows to change the plate separation and the plate area of the capacitor and collect data for the values given in Table 1. Note: If you cannot get the exact value for area, record your value and use it in calculations. Data Table 1: Relationship of the plate area and the separation of plates with Capacitance of a capacitor[10 pts] Area Trial Plate Plate Plate Area ( A) Capacitance (C) |Capacitance/ Separation PlateSeparation(d) Separation (d) Area(A) F F/mm2 mm mm mm 10 LOO 5 A CO N H 100 10 200 5 200 5 10 300 6 5 300 10 100 8 5 400 1. Consider the last column of Table 1 (the ratio between area/separation and Capacitance). Compare your findings with theory equation (3.2) and calculate a value for co, the permittivity of vacuum. What are the units of zo ? [5 points] D Now click on the Dielectric tab at the top of the simulator. Check Capacitance in the Meters menu on the right side menu. Set the plate area to 400 mm and separation to 10 mm. Slide the dielectric between the plates. Set the battery voltage to +1.5 V to charge the capacitor Measure the capacitance with the different dielectrics listed in Table 2. The dielectric material is changed by using the drop down menu on the right. Table 2: Capacitance with different dielectric materials [5 points] Dielectric Material Dielectric constant Capacitance (F) Vacuum Teflon Paper Glass Custom 5 306. From the right side menu, check Stored Charge to display the total amount of charge drawn from the battery. What is the total charge drawn from the battery in the above experiment? How does this value compare with the stored charge in Capacitor A and Capacitor B? [10 pts 7. Now add another capacitor to the circuit. Under Circuits, select 3 in parallel to construct Circuit 2 in Fig. 3.2. Set Capacitor B to 2.00 x10-13 F and the Capacitor D to 3.00x10-13 F. Set the battery to 1.5V to turn it on. Use the voltmeter to measure the voltage across each capacitor and record the absolute value in the table below. Fill in the bottom row of the table by calculating Q for each capacitor using equation 3.1 and determining the total charge drawn from the battery in this circuit. [10 pts] CA = 1.00 X 10-13 F CB = 2.00 x 10-13 F CD = 3.00 x 10-13 F AVA = AVB = AVD = AV battery= 1.5 V QA= QB= Q D = 2Total = Part 3: Capacitors in series Capacitors can also be connected in series. Capacitors in series are connected end to end as shown in Fig 3.3, Circuit 3 and Circuit 4. . You should still be on the Multiple Capacitors tab with the Total Capacitance and Voltmeter boxes checked in the right side menu. . Under Circuits, select 2 in series. The simulator will construct Circuit 3 from the figure below, which shows two capacitors in series. . Set Capacitor A to 1.00 x10-13 F and Capacitor B to 2.00x10-13F by moving the slider by each capacitor. Circuit # 3 Circuit # 4 Fig. 3.3: Capacitors in series 8. Set the battery to 1.5V to turn it on. Measure the voltage across each capacitor by connecting the voltmeter across the plates and record the absolute value. [5 pts] AVbattery = 1.5V, AVA = , AVB = 329. Using the set capacitance of each capacitor (CA = 1.0x10-13F, CB = 2.0x10-13 F), calculate the charge on each capacitor using the equation 2.1. [5 pts] Capacitor A Capacitor B 10. From the right side menu, check Stored Charge to display the total amount of charge drawn from the battery. What is the total charge drawn from the battery in the above experiment? How does this value compare with the stored charge in Capacitor A and Capacitor B? [5 pts] 11. Now add another capacitor to the circuit. Under Circuits, select 3 in series to construct Circuit 4. Set Capacitor B to 2.00 x10-13 F and Capacitor D to 3.00x10-13 F. Set the battery to 1.5V to turn it on. Use the voltmeter to measure the voltage across each capacitor and record the absolute value in the table below. Fill in the bottom row of the table by calculating Q for each capacitor using equation 3.1 and determining the total charge drawn from the battery in this circuit. [10 pts] CA = 1.00 x 10-13 F CB = 2.00 x 10-13 F CD = 3.00 x 10-13 F AVA = AVB = AVD = AV battery= 1.5 V QA= QB= QD= QTotal 33Name: Partner: Date: 3 Exploring Capacitors Introduction A capacitor is used to store charge. It can be made with two conductors, called electrodes, kept insulated from each other. If the electrodes are connected to a source of potential difference (e.g. the opposite terminals of a battery), the capacitor will charge. When the capacitor is fully charged, the two electrodes will have equal and opposite charges. Note that we refer this as the "charge of the capacitor," but the actual net charge on the capacitor is zero. Since the plates have equal and opposite charge, the actual net charge on the capacitor is zero. The capacitance of the device is defined as the ratio of charge, Q, on each electrode to the po- - Plate area, A tential difference, AV, across the capacitor: AV = (3.1) As shown in Fig 3.1 the simplest form of a ca- pacitor consists of two parallel conducting plates, each with area A, separated by a distance d. The charge is uniformly distributed on the surface of the plates. The capacitance of the parallel plate capacitor is given by Fig. 3.1: Parallel plate capacitor C = KEO d (3.2) Where