Pull-up Resistor

A resistor connected between a signal line and power supply voltage to ensure a defined high state when no other device drives the line.

component

Pull-up Resistor

A pull-up resistor is a Resistor connected between a signal line and the positive Voltage supply to ensure a defined high state.

Definition

Pull-up Resistors are used in digital circuits to ensure signal lines have a defined state when not actively driven. Common in I2C, buttons, and open-drain outputs.

Key Points

  • Connects signal to positive Voltage
  • Ensures high state when not driven
  • Common values: 4.7kΩ to 10kΩ
  • Required for I2C and SPI buses
  • Prevents floating inputs