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Activity 1.1.5 — Breadboarding & Circuit Prototyping

Learning Objectives

By the end of this lesson, you will be able to:

  1. Explain the purpose and structure of a solderless breadboard
  2. Identify power rails, terminal strips, and the center gap
  3. Apply best practices for breadboard circuit construction
  4. Build a simple LED circuit on a breadboard
  5. Troubleshoot common breadboard wiring problems

Materials

  • 1 Solderless breadboard (400 or 830 point)
  • 1 330 $\Omega$ Resistor
  • 1 LED (any color)
  • 5V Power Supply (Digital Trainer or Power Module)
  • Jumper Wires (Solid core 22 AWG)

Part 1: Breadboard Anatomy

Breadboards provide a reusable platform for building and testing electronic circuits.

How Breadboards Work

Inside a breadboard are metal strips with clips that hold component leads. Holes in the same row are electrically connected.

400-point breadboard

| Zone | Purpose | Connection Type | |------|---------|----------------| | Power rails | Distribute power (+ and -) | Vertical columns, full length | | Terminal strips | Connect components | Horizontal rows, 5 holes each | | Center gap | For ICs to straddle | No connection across gap |

Part 2: Best Practices

  1. ICs Straddle the Gap: Place ICs across the center gap to isolate each pin.
  2. Minimize Jumper Wires: Use component leads to bridge gaps where possible.
  3. Short Leads: Trim or bend leads to keep components flush to the board.
  4. Color Code: Use Red for power and Black for ground.

Part 3: Procedure — Simple LED Circuit

Follow the schematic below to build a basic LED circuit.

The Schematic

    +5V ----+---- R (330 ohm) ----+---- LED (anode) ---- LED (cathode) ---- GND

Build Steps

  1. Place the resistor with one lead in a terminal strip and the other in the positive (+) power rail.
  2. Place the LED with the anode (long lead) in the same row as the resistor output.
  3. Connect the LED cathode (short lead) to the ground (-) power rail.
  4. Connect the power module (+5V and GND) to the breadboard rails.

Part 4: Procedure — Parallel LED Challenge

Objective: Modify your circuit to include a second LED in parallel with the first. Both LEDs should light with equal brightness.

Challenge Constraints

  • Use a single resistor to limit current for both LEDs.
  • Both LEDs must be clearly visible in your photo.

Conclusion Questions

Answer the following questions based on your laboratory experience.