In this project I explored the basic properties of a resistor and discovered some important electronic formulas.
“A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.” (Wikipedia). In a simple circuit which powers a light emitting diode (LED), a resistor limits the amount of the passing electric current.
According to Wikipedia, “Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points. “. Using this law we can calculate the value of the resistor that we will use for the LED circuit. Since the overall voltage and current of the LED light is known (V = 1.8V I = 20m) finding the needed resistance will be a piece of cake.
The voltage of the resistor will be equal to the voltage minus the voltage of the LED, because they have a parallel connection. It will also have the same current as the LED.
The voltage on the battery is 5 volts, whilst the voltage on the LED is 1.8 volts. The voltage of the LED needs to be subtracted from the battery’s voltage, and the result is 3.2 volts. Using this we can then calculate the value of the needed resistor with ohm’s law. After looking at the data sheet of resistors we now know that the closest value to 160 ohms that we can use is 200 ohms.