Electrician's Home
Back to knowledge base
Basic Theory

Voltage Concept and Measurement

Voltage Concept and Measurement Definition of Voltage Voltage (also called potential difference) measures the ability of electric field force to do work. The vo…

About 5 min read beginner
VoltageMeasurementMultimeterBasics

Voltage Concept and Measurement

Definition of Voltage

Voltage (also called potential difference) measures the ability of electric field force to do work. The voltage between two points equals the work done by the electric field force when moving a unit positive charge from one point to another.

Voltage Units

  • Base unit: Volt (V)
  • Conversions:

    • - 1kV = 1000V

    - 1V = 1000mV

    - 1mV = 1000μV

    Common Voltage Values

    ObjectVoltage
    Dry battery1.5V
    Lead-acid battery2V/cell
    Phone battery3.7V
    USB interface5V
    Car battery12V
    Household electricity220V
    Industrial electricity380V

    Voltage Measurement

    Multimeter Measurement Method

  • Select appropriate range
  • Connect red probe to positive, black to negative
  • Connect in parallel to the circuit
  • Read the value

    • Precautions

  • Confirm range before measurement
  • Pay attention to polarity for DC
  • Use caution when measuring high voltage
  • Avoid over-range measurement

    • Voltage Types

    DC Voltage

  • Direction is constant
  • Magnitude may vary
  • Example: Battery output

    • AC Voltage

  • Direction changes periodically
  • Sine wave is most common
  • Example: Household power

    • Voltage and Electric Potential

  • Electric potential: Potential difference at a point relative to a reference point
  • Voltage: Potential difference between two points
  • Relationship: Uab = φa - φb
    • After reading

    Continue with the matching calculator

    A calm bridge from explanation to practice: use the calculator that matches this topic without leaving the learning flow.

    Recommended toolohm's law calculatorV = I × R · P = V × I · P = I² × R

    Ohm's Law Calculator

    Turn the article concept into a live calculation, then verify the formula, units, and result interpretation.

    Open calculator
    Electrical Power

    Electrical Power Calculator

    Use this as a follow-up check to connect the same concept with the next practical workflow.

    Voltage Drop

    Voltage Drop Calculator

    Use this as a follow-up check to connect the same concept with the next practical workflow.