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, and the output voltage is taken from the junction between these resistors. The output voltage is a fraction of the input voltage, and the ratio of the resistors determines the voltage division.
The basic principle behind a voltage divider is Ohm's law, which states that the voltage across a resistor is proportional to the current passing through it. In a series circuit like the voltage divider, the current is the same through all resistors. Thus, the voltage drop across each resistor is proportional to its resistance value.
The formula to calculate the output voltage of a voltage divider is:
Vout = Vin * (R2 / (R1 + R2))
Where:
Vout is the output voltage.
Vin is the input voltage.
R1 is the resistance of the first resistor.
R2 is the resistance of the second resistor.
To design a voltage divider circuit, follow these steps:
Determine the desired output voltage (Vout) and the input voltage (Vin) that you want to divide.
Choose suitable resistor values for R1 and R2. You can use standard resistor values or calculate the exact values you need.
Calculate the ratio of the resistors (R2 / (R1 + R2)). This ratio will determine the fraction of the input voltage that appears at the output.
If the calculated resistor values are not standard, select the nearest standard resistor values that are available and re-calculate the output voltage to ensure it meets your requirements.
Connect the chosen resistors in series, and the output voltage will be taken from the junction between the resistors.
Keep in mind that voltage dividers have limitations, and the most important one is that they are sensitive to changes in load resistance. If the load connected to the output consumes significant current, it can alter the output voltage due to the voltage drop across the load. In such cases, additional circuit elements, such as operational amplifiers, can be used to buffer the output and provide a stable voltage.