# Lab4Report (1).docx - Shyam Nath PHYS 2240.509 Experiment 4...

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Shyam Nath February 28, 2021 PHYS 2240.509 Experiment 4: Series and Parallel Circuits
Abstract The experiment verifies the relation between voltage, current and resistance which is known as Ohms Law. Also, the equivalent resistance of a parallel circuit i.e., reciprocal summation of each resistance and for series circuit, summation of each resistance. AC/DC Electronics Laboratory will be used to create a circuit with resistors and connecting wires. DC power supply will be used to pass the voltage through the circuit. Multimeter will be used to measure current at each resistor which will be compared to the theoretical values of each resistance using color coded resistance table. The error percentage was 0.77, 4.95, 3.2, and 2.5 respectively for circuit diagram 1,2,3, and 5 which is less than 5 and significantly low. Ohms Law is the basic principle in electricity and is used in almost all electric components to balance current, voltage and resistance in the system. Introduction Equivalent Resistance Resistor is the element in the electric circuit which resists or reduce the flow of current. Resistor obeys Ohm’s Law and has certain value of resistance R which can be constant or a variable. Ohms Law: V = IR (1) Where V is the potential difference which is measure in Volt(V), resistor with resistance R measured in Ohms(Ω) and I is the current through the resistor measured in Ampere (A). Resistors can be connected in series or parallel or combination of both. For series connection, current across the circuit remains constant while voltage drops across each resistor depending upon the resistance. For parallel connection, voltage across the circuit remains same while the current divides across each resistor. Equivalent resistance is the resistance which is value of resistance they can replace the given combination of resistors. Suppose two resistors with resistance R 1 and R 2 are connected in parallel and hence have constant voltage, then equivalent resistance R eq is given by: Current across resistor R 1 : I 1 = V R 1 Current across resistor R 2 : I 2 = V R 2 Then, equivalent current across the circuit is given by, I eq = I 1 + I 2
V R eq = V R 1 + V R 2 1 R eq = 1 R 1 + 1 R 2 (2) Taking reciprocal, R eq = R 1 R 2 R 1 + R 2 (3) Similarly, for series circuit which has constant current, Voltage across resistor R 1: V 1 = I R 1 Voltage across resistor R 2 : V 2 = I R 2 Then equivalent voltage across the circuit is given by, V eq = V 1 + V 2 I R eq = I R 1 + I R 2 R eq = R 1 + R 2 (4) Figure 1: Resistors in Parallel circuit (left) and in Series Circuit (Right),
Figure 2: Resistors in parallel and series combination, - eme/Edu/series-parallel-circuits Power Power is the rate at which work is done. Like work done by any machine or human, work is done by electrons to generate electric power.
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