# Physics lab report of Circuits Essay

Ohm’s law and how they are part of an operation of an electric circuit. Introduction: This experiment was done in two parts. The first part consisted of understanding how to determine the current, voltage and resistance as part of Ohm’s law. The second part consisted of how to use the variables in an electrical current.

Knowing how the variables are used in calculations and electrical currents is important in determining the value of the resistor and how it affects the current in the circuit. A device known as the millimeter is used to find the voltage and current in the circuit. Ohm’s principal discovery was that the amount of electric current through a metal conductor in a circuit is directly proportional to the voltage impressed across it, for any given temperature. Ohm expressed his discovery in the form of a simple equation, describing how voltage, current, and resistance interrelate: V= IR equation

This continuous movement of free electrons through the conductors of a circuit is called a current (l). Current is often referred to in terms of “flow. The force motivating electrons to “flow” in a circuit is called voltage, which is a specific measure of potential energy which is always relative between two points. When there is a certain voltage present within the circuit it means the measurement of how much potential energy exists to moves the electrons from one particular point in the circuit to another particular point.

In parallel, the equations are a little different, 1/ARQ = 1/RE + 1/RE + 1/RE Equation (5) ‘CEQ = II + 12 + 13 Equation (6) vex = VI = iv=iv Equation (7) Apparatus & Procedure: Procedure of part one of this experiment was, decode the resistance values by the colors of the five resistors available to you. Once all five have been decoded, record values in excel. Then construct a circuit using a D-cell battery, electronics lab board and wire leads as shown in figure 3. 1 A.

Once that has been completed, insert the red wire and black wire into the millimeter and insert the red on the positive side of the eatery while making sure the black wire is in upper left section of the lab board. Keep in mind that the millimeter sensitivity should be at mamma range. Now you can place the resistor in the circuit to determine the readings. After determining the values of the five resistors, disconnect the millimeter in order to connect a wire from the positive end to the resistor. Make sure to change the millimeter to voltage scale and reconnect the wires as shown in figure 3. 1 b.

Now you can measure the voltage with a resistor in the current and record these values in the table. Be sure to do this tit every resistor. Part 1 sample equations: Voltage/Resistance = Current (V/R=I). In part two of this experiment, use the same equipment was in part one. Pick three resistors and insert them in the board as series as shown in figure 6. 1 below while keeping in mind that they need to be connected with additional wires to complete the circuit. Then connect two wires to the battery cell. Put the scale back to mamma, now that the current is complete it must be interrupted by connecting the red wire to the positive terminal.

Then connect the black wire to the resistor 1 as shown figure 6. 3. Record he reading of 10 which is initial current. For parallel circuit, set the board as shown in figure 6. 4 below. Repeat the previous procedure, and interrupt the circuit in order to connect the millimeter at certain points in order to measure the currents of each resistor. Table I-Using values of current and resistors to find voltage: can be found in the appendix A of this report. Graph 1 of resistance vs. current can be found in appendix A. Graph 2 of current vs. voltage/resistance can be found in the appendix A.