1. What is Drift Velocity?

Drift velocity is the average velocity attained by charged particles, such as electrons, in a material due to an electric field. In general, an electron will propagate randomly in a conductor at the Fermi velocity.

2. How Does the Calculator Work?

The calculator uses the drift velocity equation:

Where:

• \( v_d \) — Drift velocity (m/s)
• \( I \) — Electric current (A)
• \( n \) — Charge carrier density (1/m³)
• \( e \) — Elementary charge (1.602 × 10⁻¹⁹ C)
• \( A \) — Cross-sectional area (m²)

Explanation: The equation shows that drift velocity is directly proportional to the current and inversely proportional to the charge carrier density, elementary charge, and cross-sectional area.

3. Importance of Drift Velocity

Details: Understanding drift velocity helps in designing electrical circuits, analyzing conductor behavior, and calculating current densities in various materials.

4. Using the Calculator

Tips: Enter current in amperes, charge carrier density in particles per cubic meter, elementary charge in coulombs (default is 1.602e-19 C), and cross-sectional area in square meters.

5. Frequently Asked Questions (FAQ)

Q1: What is typical drift velocity in copper wires?
A: Typically about 0.0001 m/s (0.1 mm/s) for 1 A current in 1 mm² copper wire.

Q2: Why is drift velocity so slow compared to electrical signal speed?
A: Electrical signals propagate at near light speed through the electromagnetic field, while individual electrons move much slower.

Q3: How does temperature affect drift velocity?
A: Higher temperature increases resistance, which may decrease drift velocity for a given voltage.

Q4: What's the difference between drift velocity and Fermi velocity?
A: Fermi velocity is the speed of electrons at Fermi level (very fast), while drift velocity is their net movement due to applied field (much slower).

Q5: Can drift velocity exceed the speed of light?
A: No, drift velocity in normal materials is many orders of magnitude below light speed.