- Experiment 4 Kirchhoff S Laws Current Divider Voltage Divider 4 1 Objective The Objective Of This Experiment Is To I 1 (67.94 KiB) Viewed 51 times
Voltage Divider In électronic circuits developing more than one voltage level from a single voltage supply is necessary. One way of doing this is by using a voltage-divider circuit. Va Figure 4.3 From Kirchhoff's current law, R, and R, carry the same current. Applying Kirchhoff's voltage law around the closed loop yields V = iR, + IR Vs R1 + R2 VS Ohm's law can be used to calculate V, and V2 R Vi = iR = V R. + R2 R2 V2 = iR, = V R + R2 Current Divider The current divider circuits divides the total current into fractional parts. The circuit shown in Fig.4.4 consists of two resistors connected in parallel across a current source. The current divider is designed to divide the current is between R, and Rz. Figure 4.4 The relationship between the current is and the current in each resistor (that is 11 and 12) can be found by directly appliying Ohm's law and Kirchhoff's current law. The voltage across the parallel resistors is V = i R1 = 13R2R, + R2 RR2 R2 11 = R1 + R2 R i:= is R1 + R2 2
4.4 Preliminary Work 1. Calculate the voltages and currents of the resistors(R1,R2,R3) for figure 4.5. 2. Use current division to find i, and use voltage division to find V, for the circuit shown below. 400 360 8А 100 100 240 440 2011 4.5 Procedure Kirchhoff's Lows 1. Using the resistors colors code, find out the resistor values for the given two resistors. 2. Set up the below given circuit figure 4.5 on the board. 3. Measure the indicated current and voltage values for all the components in the circuit. Fill in your results in Table 4.1 and Table 4.2. R1-470 Ohm Ammeter 2 DC V Source 12V Mesh 1 Mesh 2 W R1470 Ohm R3-330 Ohm Figure 4.5 Voltage Divider 4. Connect the circuit shown in Fig. 4.6, take R1=820, R2 = 1000 and R3 =1800. 5. Measured the voltage and current of "R1, R2 & R3". Fill Table 4.3. 6. Exchange the value of resistors as following: R1= 10K0, R2= 10000, R3= 500. Repeat step (5). Fill Table 4.4. R1 R3 R2 w Figure 4.6 3
Current Divider 7. Connect the circuit shown in Fig.4.7. take R1=820, R2 = 1000, R3=4700, and R4=6800 8. Measure current and voltage of R1, R2, R3, and R. Fill Table 4.5. 9. Exchange the value of resistors as following: R1= 10K0, R2= 10000, R3=2,7K, and R4=2,2K. Repeat step(8) and fill Table 4.6. 12V RI R4 Figure 4.7 Measured mA 4.6 Results Table 4.1 Kirchoff Current Law KCL Calculated mA TV lei 1R2 les KCL node1 + 11 = KCL node2 - Italia Table 4.2 Kirchoff Voltage Law KVL Calculated Measured V V Vs Vri V2 VR3 KVL mesh1 - Vs+V+V2= KVL mesh2 V-V Table 4.3 Measured Voltage(V) Calculated Current (1) Measured Current(0) Calculated Voltage(V) Voltage % error R1: R2: R3: Table 4.4 Measured Voltage(V) Voltage % error Calculated Current (0) Measured Current (0) Calculated Voltagel R1: R2: R3: Table 4.5 Calculated Current() Measured Current (1) Current % error Calculated Voltage(V) Measured Voltage(V) R1: R2: R3: R4:
Table 4.6 Calculated Current() Measured Current() Calculated Measured Voltage(V) Voltage(V) Current % error R1: R2: R3: R4: In this part comment the results. 4.7 Questions: 1. Is there any 'Voltage Law' for nodes? If so, what is it? 2. Is there any 'Current Law'for meshes? If so, what is it? 3. Components currents references are given in the figure, any change of these current references will not affect the resulting current values, why? 4. After the determination of the currents references, can we connect the ammeter terminals in any way in order to measure the current of a component? 5. Can we select components voltage references randomly in order to write KVL? Why? 6. In what situation we cannot select both current and voltage references randomly? Why? 7. Why independent KVL and KCL equations used? What happens if dependent equations are used? 8. Analyze the experiment circuits and calculate elements powers and energies.