Electric Current: Complete Guide to Electrical Flow & Measurement

Types of Electrical Current

01. Direct Current (DC):

• Charge flows in one direction (unidirectional).
• Examples: Batteries, solar cells, electronic devices like laptops.
• Characteristics: Constant or slowly varying magnitude.

02. Alternating Current (AC):

• Charge flow reverses direction periodically (sinusoidal waveform in most cases).
• Examples: Household power supply, industrial systems.
• Characteristics: Varies with time, typically at 50 Hz (Europe) or 60 Hz (North America).

03. Pulsed Current:

• A variant of DC or AC with intermittent bursts of charge flow.
• Examples: Used in medical devices (e.g., defibrillators) or digital circuits.

Ohm's Law (Relationship with Voltage & Resistance)

This formula shows that current is directly proportional to voltage and inversely proportional to resistance.

• V: Voltage (Volts)
• R: Resistance (Ohms)
• I: Current (Amps)

:

Current in Series and Parallel Circuits

Series Circuit:

Current is the same through all components.

I = I₁ = I₂ = I₃...

Parallel Circuit:

Total current is the sum of the individual branch currents.

I = I₁ + I₂ + I₃...

How is Current Measured?

Device: Ammeter (connected in series).

Where:

• I = Current (A)
• Q = Charge (Coulombs)
• t = Time (seconds)

Current Density

Where:

• J: Current density (A/m²)
• I: Current (A)
• A: Cross-sectional area of the conductor (m²)

Units of Current

About the Author

Md Jony Islam: Multidisciplinary Engineer & Financial Expert:

Md. Jony Islam is a highly skilled professional with expertise in electronics, electrical, mechanical, and civil engineering, as well as finance. Specializing in transformer service and maintenance for 33/11kV substations, he ensures reliable and efficient electrical systems. His mechanical engineering skills drive innovative designs, while his financial acumen supports effective project budgeting. With a strong foundation in civil engineering, he contributes to robust infrastructure development. Md. Jony Islam's multidisciplinary approach ensures efficiency, quality, and reliability across all projects.