Potentiometer in the context of "Panning (audio)"

A wah-wah pedal, or simply wah pedal, is a type of effects pedal designed for electric guitar that alters the timbre of the input signal to create a distinctive sound, mimicking the human voice saying the onomatopoeic name "wah-wah". The pedal sweeps a band-pass filter up and down in frequency to create a spectral glide. The wah-wah effect originated in the 1920s, with trumpet or trombone players finding they could produce an expressive crying tone by moving a mute in, and out of the instrument's bell. This was later simulated with electronic circuitry for the electric guitar when the wah-wah pedal was invented. It is controlled by movement of the player's foot on a rocking pedal connected to a potentiometer. Wah-wah effects may be used without moving the treadle as a fixed filter to alter an instrument’s timbre (known as a "cocked-wah"), or to create a "wacka-wacka" funk-styled rhythm for rhythm guitar playing.

An auto-wah pedal uses an envelope follower to control the filter instead of a potentiometer.

In American English, a set screw is a screw that is used to secure an object, by pressure and/or friction, within or against another object, such as fixing a pulley or gear to a shaft. A set screw is normally used without a nut (which distinguishes it from a bolt), being screwed instead in a threaded hole drilled in only one of the two objects to be secured. A set screw is often headless and threaded along its entire length, so that it will sit entirely inside that hole; in which case it may be called a grub screw or blind screw.

Once fully and firmly screwed into the first object, the projecting tip of the set screw presses hard against the second object, acting like a clamp. The second object may have a machined detent (recess) to ensure that it cannot slide under the tip of the screw. On a shaft, this may be simply a flattened area. A set screw may have any type of drive, such as hex or square head, slot, or recessed --- cross (Phillips), hex (Allen), star (Torx), or square (Robertson).