WORKBENCH 05 / 7 MIN TO EXPLORE
Interactive Breadboard Tutor
See what connects beneath the surface. Then build your first LED circuit, one connection at a time.
LOOK UNDER THE SURFACE
What connects to this hole?
Choose a hole. Every highlighted hole shares the same internal metal strip.
On this model, split rails break between rows 6 and 7. The left and right rails are always separate.
STEP 1 OF 4
Bring positive power to row 3
Lesson parts: 5 V DC supply · 1 kΩ resistor · red LED (2 V nominal).
This lesson uses continuous power rails. The virtual supply stays off while you place parts.
A1 connects internally to A1, B1, C1, D1, E1.
Internally connected holes
A1 · B1 · C1 · D1 · E1
Keyboard: Tab onto the board, use arrow keys to move, then Enter or Space to choose a hole. You can also use the hole picker above.
On smaller screens, scroll the board sideways to see every column.
● Highlight = same internal stripRing = selected holeFilled dot = inserted lead
Choose a hole to see what connects.
Placed components
- No components placed. Start the LED lesson to build a circuit.
THE CONNECTIONS YOU CAN’T SEE
Five holes share one metal strip.
On this practice board, A–E in each numbered row form one connected group. F–J in that row form another. The center gap separates the two groups. A4 and E4 connect internally; E4 and F4 do not.
Power rails run along the edges.
L+ and L− are the left rails; R+ and R− are the right rails. The + and − markings are labels, not a source of power. The rails only become positive and negative when you connect a supply. Opposite rails do not connect automatically.
Some real breadboards split their rails into sections. Toggle split rails to see a break between rows 6 and 7. Other boards use different layouts, so check the markings and continuity with power disconnected.
Keep component leads on separate nodes.
If both resistor leads go into one connected strip, the strip bypasses the resistor. The LED also needs its anode and cathode on different nodes, the right polarity, and a series resistor to limit current.
3 V ÷ 1,000 Ω = 0.003 A = 3 mA
The lesson is a guided connection model with nominal component values. It is not a general circuit simulator or a measurement of LED brightness. Use a current-limited low-voltage supply and check your LED’s datasheet before building a real circuit.
Explore further: calculate an LED resistor ↗
References: SparkFun’s breadboard guide and LED guide.