A passive component tying a digital input or output to the circuit ground. It prevents the pin from floating in an undefined voltage state when no active device is driving it. When a switch or active output drives the line high, it easily overcomes the weak pull-down resistance.
Heard on the job
Add a 10k pull-down resistor to the gate of that MOSFET so it stays firmly off while the microcontroller is booting.
Also heard as
- pull-down
Do not mix it up with
- Pull-up resistor: A pull-down ties to ground to default low, while a pull-up ties to VCC to default high.
Related terms
Pull-up resistor
A resistor connected between a logic pin and a positive supply voltage to hold the line at a logic high state.
Logic low
The lower of two voltage states used to represent a binary zero in a digital circuit.
Floating ground
A zero-volt reference point in a circuit that is intentionally isolated from earth ground.