Voltage Dividers Explained: What are They and How Do They Work?

What are Voltage Dividers?

What Do Voltage Dividers Do?

• Voltage Reduction: V_in, the higher voltage source, can be stepped down to V_out, the required lower voltage, in a controlled manner.
• Voltage Biasing: To power components or bias transistors, they are employed to create particular voltage levels (V_out) at different locations in a circuit.
• Voltage Ratio Setting: The resistor values (R1 and R2) can be accurately adjusted to control the ratio of the output voltage (V_out) to the input voltage (V_in).

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Voltage Divider Examples

• Voltage Regulation: A voltage divider can be used to control the voltage applied to a delicate electronic component when the source's voltage is too high.
• Analog-to-Digital Converters (ADCs): In many ADC circuits, voltage dividers are essential components that aid in reducing analog voltage signals to a range appropriate for digital value translation.
• LED Brightness Control: You may regulate the brightness of LEDs by changing the resistance values in a voltage divider circuit.
• Sensor Biasing: To supply a particular biasing voltage for different sensors inside a circuit, voltage dividers are frequently utilized.

How Voltage Dividers Work?

1. Current Flow: Current (I) passes through both resistors when the input voltage is applied to the resistors' series circuit. The voltage source's potential difference (voltage) is what causes this current flow.
2. Voltage Drop Across Each Resistor: The voltage drop across each resistor is determined by multiplying the resistance (R) of the resistor by the current (I) passing through it, as per Ohm's Law (V = I * R). There will be a voltage drop across each resistor (R1 and R2) in the series circuit as current passes through them.
3. Output Voltage (V_out): At the junction of the two resistors (R1 and R2), the desired output voltage (V_out) is obtained. Because some voltage is lost across each resistor, this voltage is always lower than the input voltage (V_in).

How to Calculate Voltage Dividers?

• V_out: This is the output voltage that you are trying to reach.
• R2: The second resistor in the series circuit, which is normally where the output voltage is taken, has this resistance.
• (R1 + R2): This is the voltage divider circuit's total resistance. It is just the total of the resistances of the two series-connected resistors (R1 and R2).
• V_in: This is the voltage that your source (power supply or battery) is providing as input.

1. Determine the Values:  assemble data regarding the input voltage and resistors:
   • R1: The initial resistor's resistance (measured in ohms, Ω).
   • R2: The second resistor's resistance, expressed in ohms (Ω).
   • V_in: The source's input voltage, expressed in volts (V).
2. Determine the Total Resistance:  To determine the circuit's overall resistance, add the resistances of R1 and R2:
   • Total Resistance = R1 + R2
3. Apply the Formula:  Enter V_in, R2, and total resistance (R1 + R2) in the formula:
   • V_out = (R2 / (R1 + R2)) * V_in
4. Find the V_out solution:  Compute the output voltage (V_out) by simplifying the formula.

Tips for Using Voltage Dividers

• Choose the Right Resistor Values: Taking into account the required output voltage and current, choose resistors with the right resistance values and power ratings.
• Think About Tolerance: Tolerances in resistors can impact how accurate the output voltage is. When controlling voltage more precisely, use resistors with finer tolerances.
• Effects of Loading: When attaching a circuit to the voltage divider output, take into consideration the loading effect. To reduce the effect on output voltage accuracy, use circuits with high impedance.

Where Are Voltage Dividers Used?

• Power Supply Circuits: They are employed in power supply circuits to produce various voltage levels that are needed to power different parts of a device.
• Microcontrollers and Logic Circuits: To bias transistors and integrated circuits in microcontrollers and logic circuits, voltage dividers are utilized to supply particular voltage levels.
• Sensor Interfaces: They are used to reduce sensor output voltages to a range that is acceptable to the processing unit in sensor interface circuits.
• Audio Circuits: Voltage dividers can be used to adjust signal levels within audio circuits.

Voltage Divider Limitations

• Power Dissipation: Heat is released from resistors by voltage dividers. When utilizing low-wattage resistors or high input voltages, this may be an issue. It's important to select resistors with the right power ratings.
• Output Current Limitations: High currents are not recommended to be supplied to circuits via voltage dividers. The input voltage and the voltage divider's total resistance determine the amount of current that is available at the output.
• Loading Effect: The output voltage accuracy may be impacted if the circuit that is connected to the voltage divider output draws a sizable amount of current. This is due to a voltage drop brought on by the extra current passing through the output resistor, which lowers the available output voltage.

Conclusion