Robotics Glossary: Plain-Language Definitions

Plain-language definitions of the robotics and electronics terms this site uses. Short on purpose. Follow the links for the full explanation.

Electronics

ADC (analogue to digital converter): turns a voltage into a number a microcontroller can read.
Brownout: a supply dip low enough to reset or upset a microcontroller. See the ESP32 brownout fix.
Decoupling capacitor: a small capacitor near a chip’s supply pins that smooths short current spikes.
GPIO: general purpose input/output, a pin you can set as an input or an output.
I2C: a two-wire bus for talking to sensors and displays. See I2C device not found.
Level shifter: a circuit that converts signals between voltages such as 3.3 V and 5 V.
Logic level: the voltage a chip treats as high or low.
PWM (pulse width modulation): switching a signal on and off quickly; the share of time it is on is the duty cycle.
Pull-up resistor: a resistor that holds a line high until something pulls it low.
SPI: a fast bus using separate clock, data in, data out and select lines.
UART: asynchronous serial, the link used by the Arduino Serial Monitor.

Buck converter: a switching regulator that steps a voltage down efficiently.
C-rating: the maker’s claimed discharge rate of a battery as a multiple of its capacity. Treat it as a claim, not a guarantee.
LDO: low dropout linear regulator; simple but it wastes the voltage difference as heat.
Voltage sag: the drop in battery voltage when a load draws current.
Wh (watt-hour): energy; volts times amp-hours.

Backlash: play between meshing gears that causes lost motion.
BLDC motor: brushless DC motor, driven by an electronic controller.
Degrees of freedom (DOF): the number of independent motions a mechanism has.
Encoder: a sensor that reports rotation as counts.
End effector: the tool at the end of a robot arm, such as a gripper.
Gear ratio: input speed divided by output speed; it trades speed for torque.
H-bridge: a circuit that lets a controller drive a motor in both directions.
Stall torque: the torque a motor produces when held from turning, usually at its highest current.
Stepper motor: a motor that moves in fixed steps.
Torque: turning force, force times distance.

Dead reckoning: estimating position from motion alone, so error grows over time.
Forward kinematics: joint angles to end effector position.
Inverse kinematics (IK): end effector position to joint angles. Try the robot arm playground.
Odometry: position estimated from wheel motion.
PID controller: a controller that combines proportional, integral and derivative terms of the error.
Setpoint: the target value a controller tries to reach.
Singularity: an arm pose where it loses the ability to move in some direction.
SLAM: building a map while estimating position inside it.

Cobot: a collaborative robot designed to work near people under a safety assessment. See the cobot buying guide.
PLC: programmable logic controller, an industrial computer for machines and cells.
ROS 2: an open robotics software framework. See the robots hub.
URDF: a file format that describes a robot’s links and joints. Check one in the URDF viewer.
Teach pendant: the handheld unit used to jog and program an industrial robot.

Missing a term? Use the contact page. More background is in the Learn hub.

Last reviewed: November 2026. Free to copy and adapt for your own project, with credit. Written, checked and maintained by Jignesh Panchal of Jaadu Digital. See the editorial standard.