Pull-Up/Pull-Down Resistor
makerA resistor used to ensure a known voltage level at a high-impedance input pin.
expanded
Pull-up and pull-down resistors are used to force an input pin to a known state when no active driver is present. A pull-up resistor connects the pin to a high logic level (e.g., 5 V or 3.3 V), while a pull-down resistor connects it to low level (e.g., ground). They are essential in preventing floating voltages which can lead to undefined behavior in digital circuits.
examples
In a microcontroller GPIO setup, a 10 kΩ pull-up resistor is connected to a GPIO pin to keep it high unless an external switch is pressed.
Used to prevent floating input values in embedded systems, ensuring reliable high logic level detection.
Using a 4.7 kΩ pull-down resistor on an unused digital input pin of a microcontroller to maintain a logical low state in the absence of an input signal.
Commonly used in industrial control circuits to avert misuse of open input pins.