Background Theory Of Ohm's Law

In this report I will show the background theory and explain the following concepts: voltage, current, resistance, Ohm’s law, serial and parallel connections. Methodology or the experimental part will explain and study the Ohm’s law discussing the point that voltage is proportional to the current and resistance is the constant of proportionality. The results of this experiment will then be expressed in a table and a graph.

Voltage (V)

Voltage is measured by a voltmeter in parallel its symbol is U. It is provided by cells which travel through the wire. When cells are in series they produce a higher voltage, as they act only as a one circuit compared to when in a parallel circuit every cell forms its own circuit. If the current I and the

Its International System of Units is Ampere (A) and it is measured by using an ammeter in series. Adding more cells to a series increases the current. The current will stay the same in a circuit and it is not dependant on where the ammeter is placed. Also it is not used up by the circuit so it will not decrease, as it goes through the circuit. The higher the voltage the higher the current.

Resistance (Ω)

Resistance’s symbol is R and its IS of unit is Ω (ohm). The resistance is higher when components are in series that if they would be in parallel. Electrical resistance explains the relation between voltage and current. When there is a thick wire more electrons are able to move, but when there is a wire which is thinner less electrons are able to move this is called resistance, as the. It is a force which slows down objects, like the electrons. This is why we cannot fit many electrons through a narrow wire and a wider wire by the same pressure.

Ohm’s law

Ohm’s law is meant to show the relationship between voltage, current and voltage. It is a law which states that the current in an electric circuit is equal to the voltage divided by the resistance. The whole meaning of the law is that when current is increased the voltage will also increase, but decreases when the resistance increases, yet still having the same

The equipment amount was limited and we got to use only one resistor, adjustable power source, voltmeter, ammeter and the necessary amount of wires. From these supplies we were able to plan and execute the circuit on the left.

In the circuit on the left the resistance stayed always 1,3 - 0,5 to the starting digit (35 Ω) with two exceptions where the resistance was 3,7 Ω and 2,4 Ω off the original measurement.

I have used my voltage and current readings to calculate the resistance and study the Ohm’s law and whether it worked during this experiment: if voltage is increased, the current increases and, because resistance is the ratio of the two are meant to stay the same.

Length is the independent variable (the one which is changed through the experiment) so it goes along the bottom axis. Current goes up on the side.

Results and discussion

The points on my graph are a bit scattered, but they are much more in a staight line than I thought they would be in. Purpose of this experiment was to study Ohm’s law, so I decided that the line of best fit was necessary to be in a straight line through the