DC Current
Steady level, one direction.
Current & Voltage Course
Lesson 13 of 16: AC vs DC Basics
Move step by step through the course and keep track of where you are.
Simulation
AC vs DC Basics
Learn the basic difference between direct current and alternating current using a simple side-by-side view.
DC
6.0 A
AC Peak
6.0 A
AC RMS
4.24 A
Frequency
2.0 Hz
Core idea
DC stays in one direction, while AC changes direction over time in a repeating pattern.
Simple idea: DC = one-way flow | AC = back-and-forth flow
Comparison View
Watch both current styles
The left view stays steady like DC. The right view changes back and forth like AC.
AC Current
Alternates above and below the center line.
What to Notice
Watch how the two signals behave
Focus on direction first. DC stays steady. AC rises, falls, and reverses direction as the waveform repeats.
DC Behavior
Steady
Direct current keeps the same direction and level unless the source changes.
AC Behavior
Alternating
Alternating current rises, falls, and reverses direction every cycle.
Where Used
Battery vs Mains
Batteries are DC. Home wall outlets are AC.
Summary
Beginner summary
Keep these quick ideas in mind while you compare AC and DC on the screen.
DC stays steady in one direction. AC changes direction again and again.
DC Basics
Direct current flows one way only. Batteries are a common DC source.
AC Basics
Alternating current changes direction back and forth. Home wall power is the most common AC example.
Key Difference
DC is steady and one-way. AC varies with time and reverses direction again and again.