Abstract
This report examines the concepts of voltage, amperage, and resistance in electrical circuits. These concepts, as the report shows, are related by a single Ohm’s law, which defines a proportional relationship between the variables. In particular, voltage as a potential difference between two points can theoretically be calculated as the product of amperage by resistance. The report shows an example of such calculations and also points out the possibility of comparing the theoretically detected values with the results obtained directly with an ammeter and a voltmeter. In addition, the report offers some limitations for Ohm’s law, from which it follows that this concept of electrophysics is not absolute and cannot be used absolutely in all cases.
Background
In electrophysics, the main parameters determining the properties of an electrical circuit are voltage, current, and resistance. Current should be conventionally understood as the ordered motion of charged particles, which creates an electric field (Prof Mad, 2020). If two different points of such motion, such as a complex circuit, create differences in the dynamics of electron motion, then a potential difference, or voltage, is said to exist between these points (Don’t Memorize, 2018).
To be more precise, electrons have high potential energy, so in locations where the concentration of electrons is higher, the potential of the point will be higher — this is how a potential difference (voltage) is created with areas where the concentration of electrons is lower. Physically, the potential difference is defined as the ratio of the work done by the charges to the value of that charge. More often than not, current does not flow freely through the wires because there are contingent obstacles in its path, called resistance.
Methods
In electrical circuits, however, it is not always possible to quantify the work done and the magnitude of the charge in order to determine the value of the voltage. Methodically, any of the three parameters, whether current, voltage, or resistance, can be measured using Ohm’s law for a simple circuit. This law determines that voltage can be calculated as the product of current by resistance, or V = IR. Resistance is usually a unique and labeled characteristic of resistors and is therefore indicated directly on the part. Voltage can be measured with a voltmeter, and current can be determined with an ammeter — these will be practical data. They can be compared with theoretical data calculated with Ohm’s law, for which at least two variables must be known.
Results
Applying Ohm’s Law in practice is relatively easy if you have an understanding of which variables are responsible for specific circuit parameters. For example, if a circuit with a 5-ohm resistor carries a current of 0.1 A, then the potential difference in that circuit is defined as V = (5 Ω)(0.1 A) = 0.5 V. In contrast, this formula can be transformed to determine the amount of current flowing, namely I = V/R. In this circuit, the current will then be I = (0.5 V)/(5 Ω) = 0.1 A. Depending on your particular situation, Ohm’s Law can be useful in determining theoretical values for unknown components.
Discussion
In electrical circuits, there are three fundamental parameters that determine the electrical dynamics of a circuit, namely current, resistance, and voltage. All three parameters have been shown to be mathematically related using Ohm’s law. The potential difference is always defined as the product of current by resistance; from this, if necessary, other related relations between the three variables can be found. Although Ohm’s law is easy enough to use and allows for calculations, it has obvious limitations for more complex circuits. In particular, the addition of transistors and diodes in one-way circuits, where current only flows in one direction, creates obstacles to using Ohm’s law (GG, 2021). In addition, if the circuit has non-linear components in which the current flows in proportion to the applied voltage, Ohm’s law is also inapplicable.
References
Don’t Memorise. (2018). Electric potential difference | electricity | don’t memorise [Video]. YouTube. Web.
GG. (2021). Ohm’s law – definition, formula, applications, limitations. Geeks for Geeks. Web.
Prof Mad. (2020). Voltage current and resistance explained | 3d animation [Video]. YouTube. Web.
The Organic Chemistry Tutor. (2019). What is electric potential difference? [Video]. YouTube. Web.