A voltage divider circuit is a simple electronic circuit used to divide a voltage into smaller fractions. It consists of two or more resistors connected in series across a voltage source, and the output voltage is taken across one of the resistors. The voltage across the output resistor is a fraction of the total voltage across the input voltage source.
The basic principle behind a voltage divider circuit is that the voltage drop across each resistor in a series circuit is proportional to its resistance value. The ratio of the two resistors determines the ratio of the output voltage to the input voltage.
Here's how to design a voltage divider circuit:
Select the Desired Output Voltage: Determine the desired output voltage you want to achieve from the voltage divider circuit.
Choose Resistor Values: Choose two resistor values, R1 and R2. The value of R1 should be connected to the input voltage source, and the value of R2 should be connected to ground or another reference point.
Calculate the Voltage Division Ratio: The output voltage (Vout) can be calculated using the voltage division formula:
Vout = Vin * (R2 / (R1 + R2))
Where:
Vin is the input voltage (across R1)
R1 is the resistance of the first resistor
R2 is the resistance of the second resistor
Check Resistor Values: Make sure the chosen resistor values are readily available and appropriate for your application. You might need to adjust the values to ensure that the voltage division ratio meets your requirements.
Build the Circuit: Connect the resistors in series across the input voltage source. Connect one end of R1 to the input voltage, the other end of R1 to one end of R2, and the other end of R2 to ground or your reference point.
Measure and Verify: Once the circuit is built, measure the output voltage using a voltmeter or a microcontroller's analog-to-digital converter. Verify that the actual output voltage matches your calculated value.
It's important to note that while voltage dividers are simple and widely used, they have limitations. One significant limitation is that they are sensitive to changes in load resistance. Connecting a load (device or circuit) to the output of the voltage divider can affect the voltage division ratio. If the load resistance is comparable to or smaller than R2, the accuracy of the voltage divider can be compromised.
In some applications, more complex voltage regulation or conditioning circuits might be needed to provide a stable and accurate output voltage.