Series Circuits Introduction

What Makes This a Series Circuit

A series circuit has only one path for current to travel. On the Microtrainer, you can trace the white line from the 5 V supply through:

• The switch

• The resistor

• The two LEDs

• And finally to ground

If any part of the path opens, the entire circuit stops working.

Voltage in a Series Circuit

Voltage divides across each component in the path.
Starting at 5 V, each resistor or LED uses part of that voltage.
A later video will show how to measure each drop with a multimeter.

Total Resistance in a Series Circuit

In series, resistances add together:

Rt = R₁ + R₂ + …

On the Microtrainer example:
100 Ω + 100 Ω = 200 Ω total

Adding more resistors increases the total resistance and reduces current.
This sets the stage for applying Ohm’s Law in a future lesson.

Key Takeaway

A series circuit always has one continuous path.
That path controls how current flows, how voltage divides, and how resistance adds up.