TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Mini pcb (printed circuit board) potentiometers. Potentiometers are a type of variable resistor. On ones like these, turning the small slotted knob varies the resistance to electric current across the metal contacts (small wires). Potentiometers are used in devices such as light dimmers and volume controls. Tiny ones like these are mounted onto printed circuit boards.
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