The breadboard is the standard prototyping fixture for every circuit you will build in HW-101 and most of CSA-101. By the end of the week you can read a breadboard's internal wiring, build a circuit from a schematic onto a breadboard, and avoid the three classic breadboard mistakes.
Reading (~30 min)
- The SparkFun "How to Use a Breadboard" tutorial. Read the layout section carefully
- The kit's breadboard quick-start card
Lecture (~1.5 hr)
- Breadboard anatomy. Two power rails on top; two on bottom; two main columns of tie-strips; the central gap that separates the two columns
- Internal connections. The rails are connected horizontally across; the tie-strips are connected vertically in groups of 5; the central gap separates left from right
- Schematic-to-breadboard translation. A schematic shows the electrical connections; the breadboard makes those connections physical. There are many valid layouts for the same schematic
- Color discipline. Red wires for positive power; black or blue for ground; other colors for signals. Adopt this from day 1 and you will save yourself hours over the next 11 weeks
- The three classic breadboard mistakes. Mistake 1: crossing the central gap with a tie-strip (it does not connect across). Mistake 2: powering both rails accidentally with reverse polarity. Mistake 3: leaving a long jumper wire that catches on probes and pulls connections loose
Lab exercises (~2 hr)
Lab 3.1: Breadboard Blink. Build the simplest active circuit: 9V battery → 470Ω resistor → LED → ground. The LED lights. ~60 minutes (with deliberate slowness; the point is form and discipline, not speed).
Independent practice (~3 hr)
- Build three different two-LED circuits: two LEDs in series; two LEDs in parallel; one LED in series with a different-color second LED. Measure and compare brightness
- Rebuild your week-2 voltage divider on the breadboard. Compare the breadboard-built version to whatever you had before
- Practice the color-discipline rule. Build any small circuit using only red and black wires; then rebuild it using rainbow colors with intent. Notice the readability difference
Reflection prompts
- The breadboard's internal layout is fixed. Why don't you have to memorize it from scratch? What did the breadboard's designer assume about how people would use the tool?
- The same schematic can be laid out on a breadboard many different ways. What makes one layout "better" than another? Be specific
- Reading a finished schematic vs reading a working breadboard are different skills. Which one do you find easier and why?
What's next
Week 4 introduces capacitors. The voltage divider and the resistor circuits you have built so far are static: outputs depend only on present inputs. Capacitors introduce time. Outputs start depending on past inputs too.