One path only
Current has only one route, so every component must sit in the same loop.
Current & Voltage Course
Lesson 9 of 16: Series Circuit Basics
Move step by step through the course and keep track of where you are.
Simulation
Series Circuit Basics
A series circuit has one path for current, so every component shares the same loop current.
Voltage
12.0 V
Current
0.83 A
Total R
12.0 Ohm
Loop Rule
3.3V + 6.7V + 2.0V ≈ 12.0V
Core idea
The same current flows through every component, while the voltage is shared across the parts in the loop.
Simple idea
One path means the same current in every part, while the voltage is shared across the loop.
Circuit View
Watch the series path respond
One path, same current everywhere, and voltage shared across the loop.
Circuit View
Watch the one-path behavior
This simulation shows how one complete series loop shares the same current through every part while the voltage drop is divided across the components.
Same current
0.83 A
The same current moves through resistor one, resistor two, and the LED.
Total resistance
12.0 Ohm
Adding more series resistance makes the total loop resistance larger.
Voltage sharing
10.0 V
The voltage drops across the resistors add up around the loop.
What to notice
In a series circuit, the path is one line. Because of that, current stays the same everywhere, while resistance adds up and the voltage drop gets shared across the parts.
Beginner Summary
Keep the one-path idea in mind
This lesson becomes easy when you remember one simple picture: a series circuit is one full path, so the same current moves through every component in that line.
One path means shared current. More series resistance means less current.
Same current
The current through resistor one, resistor two, and the LED is the same.
Resistance adds up
Adding more series resistance makes the total resistance larger and the current smaller.