Definition

1. Noun:
   • A variable resistor with three terminals: A "potentiometer" is an electrical component with three connection points. The third terminal is an adjustable center contact (called a wiper) that slides along a resistive element, allowing the user to precisely adjust or divide a voltage. It is commonly used for volume controls in audio equipment like radios and television sets.
   • A measuring instrument for direct current (DC) voltage: In a scientific context, a "potentiometer" is a precision instrument used to measure an unknown electromotive force (EMF) or voltage by balancing it against a known standard voltage, without drawing any current from the source being measured.

Examples of Usage

• As a variable resistor:
  • The technician replaced the faulty potentiometer to fix the crackling sound in the amplifier.
  • Turn the potentiometer clockwise to increase the brightness of the display.
• As a measuring instrument:
  • In the physics lab, we used a potentiometer to accurately measure the EMF of a cell.
  • The old potentiometer provided a more precise voltage measurement than the modern digital multimeter for that specific calibration task.

Advanced Usage

• "Potentiometer" in a circuit diagram: Refers to the schematic symbol representing the three-terminal variable resistor.
  • The voltage divider circuit in the design requires a 10kΩ potentiometer.
• "Digital potentiometer": A modern, integrated circuit that performs the same function as a traditional mechanical potentiometer but is controlled by digital signals.
  • The microcontroller adjusts the gain by sending commands to the digital potentiometer.

Variants and Related Words

• Pot (n): A common informal abbreviation for "potentiometer" in electronics, especially when referring to a variable resistor.
  • The volume pot on my guitar needs cleaning.
• Rheostat (n): A related two-terminal variable resistor used for controlling current, whereas a potentiometer is typically used for controlling voltage.
• Trimmer (or Trimpot) (n): A small potentiometer designed for occasional adjustment, often used to calibrate circuits.
  • Use a screwdriver to adjust the trimpot for the correct bias voltage.

Synonyms

• Variable resistor: General term for a resistor whose resistance can be adjusted.
• Voltage divider: Describes the primary function of a three-terminal potentiometer in a circuit.
• Measuring bridge (for the instrument): Refers to a similar null-balance measurement technique.

Related Phrases (Technical Terms)

• "Potentiometer wiper": Refers to the movable center contact of the potentiometer.
  • The signal is taken from the potentiometer wiper.
• "Potentiometer setting": The specific position or resistance value to which the potentiometer is adjusted.
  • The optimal potentiometer setting is marked on the schematic.
• "To potentiometer" (verb, rare/technical): To measure or adjust using a potentiometer.
  • The voltage was potentiometered to ensure accuracy.

Noun

1. a resistor with three terminals, the third being an adjustable center terminal; used to adjust voltages in radios and TV sets
2. a measuring instrument for measuring direct current electromotive forces