Lesson 01 · Circuits
Complete the Circuit
Tap one terminal, then another, to run a wire.
OPEN
GOAL: Make one unbroken loop: battery → switch → bulb → battery. Then close the switch.
💡 TIP — Trace the loop with your finger first: out of +, through every part, back to −.
Start at the battery’s + terminal. A bulb needs a complete loop, not just one wire.
WHY IT WORKS: Current needs a continuous path out of one battery terminal, through the switch and bulb, and back to the other terminal. The moving dashes show that closed loop.
Lesson 02 · Series cells
Build the Voltage
Cells in series add their voltages.
OPEN
GOAL: Solve three target voltages. Tap a cell to place it; tap a filled slot to remove it.
💡 TIP — Series cells just add up — two friendly 1.5 V cells make a cheerful 3 V.
TARGET
9.0 V
SERIES METER0.0 V
A single PP3 is a real 9-volt battery. Other targets need series math.
WHY IT WORKS: In series, voltages add: each cell gives the charge another push in the same direction. That is how small cells become a bigger power source.
Lesson 03 · Ohm’s law
Tune the Resistor
A 9 V source feeds a lamp rated for 0.45–0.60 A.
OPEN
GOAL: Choose resistance so I = V ÷ R lands in the safe band.
💡 TIP — Do the division before you choose: Amps = Volts ÷ Ohms.
🔋
9 VSOURCE
—〰—
💡
🧯
FUSEREADY
SOURCE9 V
RESISTOR— Ω
CURRENT— A
I = 9 V ÷ R Ω = ? A · SAFE: 0.45–0.60 A
Too little resistance lets too much current flow. Too much resistance starves the lamp.
WHY IT WORKS: Ohm’s law says current equals voltage divided by resistance. You did not just memorize the formula — you used it to choose a real operating point.
Lesson 04 · Series vs parallel
String of Lights
Same three bulbs. Two very different paths.
OPEN
GOAL: Find the wiring style that keeps the other lights on when the middle bulb burns out.
💡 TIP — Series shares the push; parallel gives every bulb the full push.
💡
Bulb 135%
💡
Bulb 235%
💡
Bulb 335%
SERIES: a 12 V supply is shared — about 4 V per identical bulb.
In series the bulbs share voltage, so they glow dimmer. Try the burnout test in both modes.
WHY IT WORKS: Series has one path, so one open bulb stops everything. Parallel gives each bulb its own branch across the full supply, so the surviving branches keep working.
Lesson 05 · Protection
The Fuse Box
Three circuits. Pick the closest safe protection.
OPEN
GOAL: Carry the load, stay at or below the wire limit, and choose the lowest rating that does both.
💡 TIP — Watts ÷ Volts gives you Amps — then pick the smallest fuse that covers them.
⚡ READY
I = 1,800 W ÷ 120 V = 15.0 A
Ratings below the load current will nuisance-blow. Ratings above the wire limit leave the wire under-protected.
WHY IT WORKS: A protective device must carry normal current but open before the wire is asked to carry more than its limit. The right answer is a match, not simply “bigger.”
Lesson 06 · Current types
AC or DC?
Judge the output each source actually supplies.
OPEN
GOAL: Sort all eight sources. Wrong answers explain themselves.
💡 TIP — Judge the output, not the label — what comes OUT is what you sort.
Correctly sorted0 / 8
AC BINEmpty
DC BINEmpty
Think about the output: batteries supply DC; household mains supply AC.
WHY IT WORKS: DC flows steadily in one direction. AC repeatedly reverses direction. Many devices use converters, so the useful question is what comes out of the source in front of you.
Keep in your pocket
Tips & Tricks
Six little rules that run every bench in the lab. Every tech leans on these — now you can too.
🔁Current needs a complete loop — out, through, and back home.
🔋Series stacks the push — 1.5 V + 1.5 V = 3 V.
➗Current = Volts ÷ Ohms — Ohm’s law, the whole game in one line.
⚡Watts ÷ Volts = Amps — the nameplate always tells you the watts.
💡Parallel bulbs each get the full push — bright, and independent.
🛡A fuse is a guard, not a suggestion — the smallest size that covers the load wins.
SAFETY FIRST: Spark Lab is an educational simulation. Real wiring can injure or kill — leave real electrical work to trained, qualified hands.
