Relationship Between Voltage and Current Essay Example
Several conclusions about the relationship between voltage and current were reached while testing the current and resistance present in a circuit set to a specific voltage. For the first experiment, a simple series circuit was made. A conducting wire connects one side of the voltage source with a switch, the switch had a conducting wire which connected it to the resistor. Finally another conducting wire connected the resistor to the other end of the voltage source. A multimeter was also used, each side of the alligator clips was connected to each side of the resistor.
Voltage is the force that pushes charged electrons through a conducting wire, while current is the movement of negatively charged electrons through a wire,it is what moves through the circuit. The electrons are able to move through a circuit because they are attracted to a positive charger, they move out of the negative enclosure and flow through a circuit to the other side of the voltage source: the positive charge. Resistance is the opposition that a substance provides in an electric charge. According to the lab results, as the voltage increased, the current increased while the resistance decreased.
The amount of resistance an object has is determined primarily by its conductivity. The conductivity of an object is classified into two types: conductors and insulators. Conductors are objects with low resistance that allow electrons to easily pass through them. Many metals are excellent conductors because there is little resistance preventing electron movement. Insulators, on the other hand, have a high resistance because of the strong opposition force that prevents negatively charged electrons from passing through. Nonmetals make up the vast majority of insulators. Water is an unusual insulator; pure water is an excellent insulator, but charged ions and impurities in water are good conductors; salty water is a fair conductor because it contains more impurities than pure water.
It was discovered that when the light bulb's voltage was set to one volt, the current measured was 1.6 amps. The current present was 4.8 amps when the voltage was set to 2.5 volts. This was calculated using Ohm's Law. Georg Ohm was a German physicist who investigated the connection between voltage, current, and resistance. He devised equations for calculating voltage, current, and resistance. Voltage (potential difference)/resistance is the current formula, resistance is voltage/current, and voltage is current*resistance. It's important to remember that even if the voltage in a circuit is the same, the current present does not have to be. For example, when tested, the motor had no exact current, whereas the light bulb had an exact current. This is due to the fact that the current of a circuit is determined by both the supplied voltage and the resistance present in the resistor; because the resistances of both resistors differ, their currents differ as well. This is why we must use ohm's law to calculate our current, voltage, or resistance.
Current is also affected by the type of circuit used; there are two types of circuits: series and parallel. A series circuit has all of its resistors connected in a single current path. After measuring the current in the series circuits, it is possible to conclude that the current and brightness decrease as the number of light bulbs increases. The series circuit made was simple, with conducting wires extending from each side of a battery and connecting to each side of the light bulb. A conducting wire is disconnected from the battery and connected to another light bulb, and another conducting wire connects the other side of the light bulb to the battery when a new light bulb is added.
The current decreases as more light bulbs are added because the circuit can only be completed when a few charges are applied to each resistor, and the more resistors added, the less charge can be applied to each of them. As a result, as the number of light bulbs increase, the current and brightness decrease. Because all resistors are connected by a single wire, if one fails, the circuit cannot be completed and no energy is produced; this is exactly what happened when one light bulb was disconnected; the others did not turn on either. Despite this significant disadvantage, because of their low manufacturing cost, series circuits are widely used. This disadvantage can be avoided by consistently checking on the quality of the resistors. Series circuits are common in items like Christmas lights and even some cheaper flashlights, but not in more complex circuits like house wiring.This is where parallel circuits come into play.
Parallel circuits have current flowing through multiple paths and resistors divided into different branches. First a simple circuit in which conducting wires were connected to each side of the voltage source was created. Then, conducting wires were connected to the main “border” to create branches. The resistor was put in these branches, when a new light bulb needed to be added, a new set of conducting wires were added to the circuit as branches.
When the current and brightness of a parallel circuit were measured, it was clear that the brightness was consistent within each light bulb and that the more light bulbs added, the higher the current. When more branches are added to a parallel circuit, the current has more paths to travel through. Because the current is not required to divide charges among a series of resistors, the resistance decreases (higher flow of electrons), and Ohm's law states that as resistance decreases, current increases. Another thing to keep in mind is that the brightness of each light bulb remains constant regardless of how many resistors are added. Because each resistor in a parallel circuit is kept separate from the other resistors, the current present at one individual branch remains constant as more resistors are added, hence the brightness does not change. In parallel circuits if one resistor fails the current can complete the circuit by going through the other branches, hence the other resistors are unaffected and continue to produce energy. Parallel circuits are used for circuits like house wiring and stoves because they last longer and produce more consistent energy than series circuits. However, because so many wires are used, they can be expensive to manufacture. In the end, both parallel and series circuits are useful in certain situations and can be found all around us.
