- ADC
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An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.
- DC
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DC means direct current, where electricity flows in one constant direction, as supplied by batteries, USB ports and many plug-pack power supplies. When a product specifies DC, it runs from a DC supply rather than mains AC, so you need to provide the correct voltage and polarity.
- GND
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GND is the ground or reference connection (0 V) for a circuit. When connecting two devices together, their grounds must be joined so both agree on what counts as a low or high signal.
- LED
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A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.
- microcontroller
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A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.
- SCL
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The clock line used by the I2C bus to keep data transfers timed between a controller and connected devices. When wiring I2C, SCL must be connected to the SCL pin on every device sharing the bus.
- SDA
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The data line used by the I2C bus to carry information between a controller and connected devices. When wiring I2C, SDA must be connected to the SDA pin on every device sharing the bus.
- Torque
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A twisting force that causes something to rotate, usually measured in newton-metres or kilogram-centimetres. It matters when choosing motors, servos, gears, and tools because higher torque is needed to lift heavier loads, turn larger wheels, or move mechanisms without stalling.
- wavelength
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The distance between repeating peaks of a wave, often used to describe the colour of light in nanometres. For visible lasers and LEDs, wavelength tells you the approximate colour, such as red, green or blue.
