A voltage divider circuit is a simple electronic circuit used to divide a voltage into smaller fractions. It's commonly used in electronics to create reference voltages, set bias levels, and scale down voltages for various purposes. The basic principle behind a voltage divider circuit is to use two resistors in series to create a fraction of the input voltage across one of the resistors.
Here's how a voltage divider circuit is constructed:
Components needed:
Two resistors (R1 and R2)
Voltage source (V_in)
Construction:
Connect one end of resistor R1 to the positive terminal of the voltage source (V_in).
Connect the other end of resistor R1 to one end of resistor R2.
Connect the other end of resistor R2 to the ground or reference potential (0V).
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V_in
+---- R1 ----+---- R2 ---- GND
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V_out
Working principle:
According to Ohm's law (V = I * R), the voltage across a resistor is proportional to the current flowing through it. When you connect two resistors in series and apply a voltage across them, a current (I) flows through both resistors. The voltage drop across each resistor is proportional to its resistance.
The voltage across R1 (V_R1) is given by:
V_R1 = (R1 / (R1 + R2)) * V_in
The voltage across R2 (V_R2) is given by:
V_R2 = (R2 / (R1 + R2)) * V_in
The voltage across R2, which is the output voltage (V_out), is the voltage we're interested in:
V_out = V_R2 = (R2 / (R1 + R2)) * V_in
By choosing appropriate values for resistors R1 and R2, you can determine the output voltage (V_out) that you want to achieve. The output voltage is a fraction of the input voltage, and the fraction is determined by the ratio of the resistances of R2 and the total resistance (R1 + R2).
It's important to note that voltage dividers are sensitive to changes in load resistance and current. If the load connected to the output consumes a significant amount of current, it can distort the voltage divider's accuracy.
Voltage dividers find application in various electronic systems, such as level shifting, sensor interfacing, and biasing transistors, among others. When designing a voltage divider, you need to consider the desired output voltage, the input voltage range, the load connected to the output, and the tolerance of the resistors used.