Potential Divider Circuits

• What is a potential divider circuit?

  A circuit that produces an output voltage

  
• How does Kirchhoff’s Second Law relate to potential dividers?

  It states voltage is divided across series resistors

  
• What are the main purposes of potential dividers?

  • Provide a variable potential difference
  • Enable a specific potential difference to be chosen
  • Split potential difference between components
• Where are potential dividers commonly used?

  In volume controls and sensory circuits
• What does the potential divider equation express?

  Voltage ratio equals resistance ratio

  
• What is the formula for output voltage in a potential divider?

  $V_{out} =$$\frac{R_1}{R_1 + R_2} V_{in}$

  
• What happens to the potential difference across a resistor with larger resistance?

  It has a greater potential difference
• What occurs if the resistance of one resistor in a potential divider is increased?

  It receives a greater share of potential difference
• How does the potential difference across a component relate to its resistance?

  It is proportional to its resistance
• What is the effect of decreasing the resistance of an LDR?

  The potential difference through it decreases
• What happens to the potential difference across a thermistor when its temperature increases?

  The potential difference across it decreases

  
• What are the characteristics of LDRs and thermistors in potential dividers?

  • LDR: Resistance decreases with higher light intensity
  • Thermistor: Resistance decreases with higher temperature

  
• In what applications are LDRs commonly used?

  Street and security lights
• In what applications are thermistors commonly used?

  Fire alarms, ovens, and digital thermometers
• How does the total potential difference relate to individual components in a series circuit?

  It equals the sum of the potential differences
• What happens to the potential difference across a resistor if the potential difference across a thermistor increases?

  The potential difference across the resistor decreases

  
• What is the relationship between current and potential difference in series circuits?

  • Current is the same through all components
  • Potential difference is shared among components
• What law states that the sum of potential differences equals the e.m.f of the supply?

  Kirchhoff’s Second Law
• What is the significance of ensuring the correct resistance is in the numerator of the potential divider equation?

  It determines the output voltage accurately

  
• What is the output voltage measured from in a potential divider circuit?

  From the center to the bottom of resistor R

  
• What happens to the potential difference across a component if its resistance increases?

  The potential difference across it increases
• How does the potential difference across a sensory resistor affect the other resistors in the circuit?

  It inversely affects the potential difference across others