Voltage Divider

Series Circuits Take a series circuit with two resistors Since each is the same resistance, they use up the same amount of voltage, 6V Therefore the voltage at point A is 6V

Series Circuit We can rearrange the circuit as shown on the right

Series Circuit And then simplify it once more

Series Circuit =

Voltage Divider It doesn’t matter the amount of resistance, if they are equal they use the same voltage The voltage at A in this case is still 6V

Voltage Divider By adjusting the ratio of the resistors, we change how much voltage each one “uses up” The resistance at A is significantly higher now since the second resistor will need much more voltage

Voltage Divider The resistance at A will now be significantly lower since the first resistor will use up most of the voltage By altering the ratio of resistors we can alter the voltage at A

Voltage Divider Suppose we replace the top resistor with a sensor that can change resistance In this case a light sensor, photoresistor, that operates from 1k – 10k based on light By measuring the voltage at A we can determine the amount of light in the room

Complete the “Sensors in a Circuit” Lab