Experiment: Using a Voltage Divider for Reference Voltage Creation

Objective

To understand how a voltage divider can provide a reliable reference voltage for circuits that require a fixed, lower voltage than the main supply.

Materials

• Two resistors (e.g., 10kΩ each, or other values depending on desired reference voltage)
• Breadboard
• Jumper wires
• Power supply or battery (e.g., 9V or 12V)
• Multimeter or oscilloscope

Circuit Diagram

Connect the circuit as shown below, with two resistors forming a voltage divider that outputs a stable reference voltage.

Theory

A voltage divider can generate a specific fraction of the input voltage. This fraction can serve as a reference voltage for various components, such as ADCs or op-amps. The output voltage V_out from the divider is calculated by:

V_out = V_in * (R2 / (R1 + R2))

where V_in is the input voltage, and R1 and R2 are the resistors forming the divider.

Procedure

1. Choose resistor values R1 and R2 to achieve the desired reference voltage. For example, if V_in is 9V and you want a 4.5V reference, use equal resistors for R1 and R2 (e.g., 10kΩ each).
2. Connect R1 between V_in (positive terminal of the power source) and the output node.
3. Connect R2 between the output node and ground.
4. Measure the output voltage V_out using a multimeter or oscilloscope.
5. Verify that V_out is consistent with the calculated value, confirming it as a stable reference voltage.

Observations

Record the measured output voltage and compare it with the calculated reference voltage based on the resistor values and input voltage.

Conclusion

This experiment shows that a voltage divider can produce a stable reference voltage for use in analog circuits, provided the load on the divider is minimal. This technique is commonly used in analog and digital electronics where a lower, stable reference voltage is needed.