A voltage divider circuit is a simple electronic circuit used to divide a voltage into smaller fractions of its original value. It consists of two resistors connected in series, with an input voltage applied across the combination, and the output voltage taken from the junction between the two resistors. This setup creates a proportional voltage drop across each resistor, resulting in an output voltage that is a fraction of the input voltage.
The voltage divider formula is given by:
out
=
in
×
2
1
+
2
V
out
=V
in
×
R1+R2
R2
Where:
out
V
out
is the output voltage.
in
V
in
is the input voltage.
1
R1 is the resistance of the first resistor.
2
R2 is the resistance of the second resistor.
To construct a voltage divider circuit, follow these steps:
Choose Resistor Values: Decide on the desired output voltage fraction and the input voltage. Then, select resistor values for
1
R1 and
2
R2 accordingly. The output voltage fraction is determined by the ratio of
2
R2 to the total resistance (
1
+
2
R1+R2).
Calculate Output Voltage: Use the voltage divider formula to calculate the expected output voltage. Make sure the output voltage is within the desired range and suitable for your application.
Connect the Resistors: Connect the resistors in series. One end of
1
R1 connects to the input voltage, and the other end connects to one terminal of
2
R2. The remaining terminal of
2
R2 is the output voltage point.
Apply Input Voltage: Connect the input voltage source across the combination of
1
R1 and
2
R2.
Measure Output Voltage: Measure the output voltage across
2
R2 or at the junction between
1
R1 and
2
R2 using a voltmeter.
Keep in mind a few considerations when designing and using voltage divider circuits:
The total resistance (
1
+
2
R1+R2) affects the current flowing through the circuit. If the total resistance is too low, it might draw excessive current from the source and cause power loss in the resistors.
The chosen resistor values should be within the range of available resistor values. Using standard resistor values (such as those from the E-series) makes component selection easier.
Voltage divider circuits are sensitive to variations in resistor values and can be influenced by the loading of the output.
For precise voltage division and better stability, it's often beneficial to use higher precision resistors.
Voltage divider circuits are commonly used in various applications, including level shifting, sensor interfacing, biasing transistors, and setting reference voltages for analog circuits.