WattsUp

Lesson 01 — Basics

What is a Circuit?

A circuit is a closed loop that allows electric current to flow. It needs a power source, a conductive path, and a load to do useful work.

🔋Power SourceProvides EMF (e.g. battery)

〰️ConductorCarries current (wire)

💡LoadConverts energy (bulb, etc.)

🔄Closed LoopCurrent must have a complete path

Lesson 02 — Ohm's Law

Ohm's Law

The relationship between voltage, current, and resistance — the foundation of all circuit analysis.

V = I × R

I = V / R R = V / I

Voltage (V)

9 V

Resistance (Ω)

100 Ω

0.09
Current (A)

90
Current (mA)

0.81
Power (W)

Lesson 03 — Series

Series Circuits

In a series circuit, components are connected end-to-end in a single path. The same current flows through every component.

Same ICurrent is identical through every component

V addsV₁ + V₂ + V₃ = V_supply

R addsR_total = R₁ + R₂ + R₃

Lesson 04 — Parallel

Parallel Circuits

In a parallel circuit, components share the same two nodes. Each branch has the same voltage but can carry different currents.

Same VVoltage is identical across every branch

I addsI_total = I₁ + I₂ + I₃

1/R1/R_total = 1/R₁ + 1/R₂ + 1/R₃

Lesson 05 — Power

Electrical Power

Electrical power is the rate of energy transfer. Three equivalent formulae let you calculate it from any two known quantities.

P = V × IFrom voltage & current

P = I²RFrom current & resistance

P = V²/RFrom voltage & resistance

Voltage (V)

12 V

Current (A)

1.00 A

12.00
Power (W)

0 W120 W max

Circuit Lab

Simulation Lab

Configure a circuit below and hit Simulate — results come from the backend calculation engine.

Series

Parallel

Builder

Series Circuit

Battery Voltage

9 V

R1 (Ω)

100 Ω

R2 (Ω)

200 Ω

R3 (Ω)