Bench Notes: Making Ohm’s Law Visible

Context (Why this caught my attention)

physical. I wanted to build a few small circuits where voltage, current, and resistance aren’t just calculated—they show up in measurable, tangible ways.

I’m looking to connect the equation to behavior:

  • How current actually responds to resistance changes
  • How power limits show up in a real component (a 1/4 W resistor)
  • How voltage distributes itself in series circuits (KVL)
  • How current splits in parallel paths (KCL)

The Relationship (anchor idea)

At the center of all of this is: $ V = IR$ where V = voltage (volts), I = current (amps), R = Resistance (ohms).

Setup (What I put together)

I worked with a small DC supply, a digital multimeter, and a handful of resistors and LEDs.

The circuits were simple:

  • LED with a series resistor
  • Two resistors in series and in parallel
  • Three resistors in series (for KVL)
  • One resistor feeding two in parallel (for KCL)

I measured resistance directly, then voltages across components, and currents through branches.

What I Did

Rather than building one “perfect” circuit, I moved through variations:

  • Started with an LED and a series resistor, adjusting resistance to see how brightness and current changed
  • Chose resistor values that would push toward (but not exceed) the 1/4 W rating
  • Reconfigured the same resistors into series and parallel arrangements
  • Built a simple three-resistor string to watch voltage division
  • Then split current into two parallel branches and compared the currents

At each step, I measured rather than assumed.