OHM'S LAW Essay

Objective: The purpose of this lab is for student's to investigate the relationship between the three variables involved in Ohm's Law- Current, Voltage, and Resistance.Theory: The Ohm's law states that the direct current flowing in a conductor is directly proportional to the potential difference between its ends. It is usually formulated as V = IR, where V is the potential difference, or voltage, I is the current, and R is the resistance of the conductor.Formulas:V=IRMaterials:1) Circuits Experiment Board2) D-Cell3) Wire4) Digital Multimeter (DMM)5) ResistorsDiagrams:AmmmeterUmm WireVolt MeterrheostatProcedure:1) Making sure that the switch is open carefully construct the circuit. W ...view middle of the document...

2) For each value of R in table V very carefully adjust the knob of the power supply until the current R is 1ma (1ma Full scale meter). For each of these values of R in table V measure the voltage with a voltmeter (12 V Full-Scale).A. Variation of current with voltage keeping R constant.1. Applying Ohm's Law, for each value of I and Vr in Table I compute R and record these values in table I.2. Determine the average value of R from Table I and record in Table II.3. Determine the average value of Vr in table III and record in table IV.B. Variation of Voltage with resistance keeping it constant.Tabulations:Table I- Variation of Current with Voltage Keeping R Constant (Part A)I (ma) Vr (volts) R (Ω) V=I x R Theoretical5 0.51 v 100 5x 10-3A x 1x102 Ω .5 x 10-1 V15 1.45 v 100 15 x 10-3 A x 1x102 Ω 15 x 10-1 V25 2.45 v 100 25 x 10-3 A x 1x102 Ω 25 x 10-1 V35 3.25 v 100 35 x 10-3 A x 1x102 Ω 35 x 10-1 V45 4.40 v 100 45 x 10-3 A x 1x102 Ω 45 x 10-1 VTable III- Variation of Current with Resistance Keeping Vr Constant (Part B)I (ma) R (Ω) Vr (volts) I= Amps4.0 mA 2K 8 8/ (2 x 103) 4x10-38.2 mA 1K 8 8/ (1 x 103) 8 x10-310.5 mA 800 K 8 8/ (1 x 102) 1 x 10-213.2 mA 600 K 8 8/ (6 x 102) 1.33 x 10-219.7 mA 400 K 8 8/ (4 x 102) 2 x 10-2Table V- Variation of Voltage With Resistance Keeping I Constant (Part C)Vr (volts) R(Ω) I (ma) V=IR2.45 v 1K 2 (2x 10-3)(1x 103) = 2V7.2 v 3K 2 (2x 10-3)(3x 103) = 6V11.7 v 5K 2 (2x 10-3)(7x 103) = 18VCalculations:Table 1 - Variation of Current with Volt...