lilernoEngineeringOpening Lilerno
Chapter 17 · Guided self-study
Intro + external course studyExplain how electrical input becomes mechanical output.
Build the idea
An original introduction, worked example and practice, followed by a curated reading sequence. The external courses supply deeper teaching and problem sets.
This guide is an orientation, not a complete university module. Practical work needs suitable facilities, safety review and supervision.
Start with these prerequisites
Shared science foundations
Electrical power can become mechanical work, but voltage, current and power describe different aspects of a circuit.
Module lens
A simple circuit connects voltage across a component, current through it and power dissipated.
An ideal resistor follows V = IR. Kirchhoff's current and voltage laws encode conservation in the lumped-circuit approximation. Real components have ratings and nonideal behaviour; Ohm's law is not a universal device law.
Electrical input power can be VI under the appropriate DC convention. Mechanical rotating-shaft power is torque times angular speed. Losses mean a real motor's output is less than its input; a model needs a stated efficiency and operating point.
See the relationship
Change one quantity, watch the graph respond, then explain the result in your own words.
Predict → change → explain
At fixed voltage, what happens to power when resistance doubles?
Axes: Voltage (V) → Current (A). Bounds may rescale when inputs change.
I = 2 A; P = 24 W.
Ideal ohmic DC resistor. This is a numerical exercise, not a component specification or hardware instruction.
Original Lilerno illustration. Inputs are illustrative; this is not experimental evidence or a design rating.
| Series | Voltage (V) | Current (A) |
|---|---|---|
| Ohmic response | 0 | 0 |
| Ohmic response | 0.3 | 0.05 |
| Ohmic response | 0.6 | 0.1 |
| Ohmic response | 0.9 | 0.15 |
| Ohmic response | 1.2 | 0.2 |
| Ohmic response | 1.5 | 0.25 |
| Ohmic response | 1.8 | 0.3 |
| Ohmic response | 2.1 | 0.35 |
| Ohmic response | 2.4 | 0.4 |
| Ohmic response | 2.7 | 0.45 |
| Ohmic response | 3 | 0.5 |
| Ohmic response | 3.3 | 0.55 |
| Ohmic response | 3.6 | 0.6 |
| Ohmic response | 3.9 | 0.65 |
| Ohmic response | 4.2 | 0.7 |
| Ohmic response | 4.5 | 0.75 |
| Ohmic response | 4.8 | 0.8 |
| Ohmic response | 5.1 | 0.85 |
| Ohmic response | 5.4 | 0.9 |
| Ohmic response | 5.7 | 0.95 |
| Ohmic response | 6 | 1 |
| Ohmic response | 6.3 | 1.05 |
| Ohmic response | 6.6 | 1.1 |
| Ohmic response | 6.9 | 1.15 |
| Ohmic response | 7.2 | 1.2 |
| Ohmic response | 7.5 | 1.25 |
| Ohmic response | 7.8 | 1.3 |
| Ohmic response | 8.1 | 1.35 |
| Ohmic response | 8.4 | 1.4 |
| Ohmic response | 8.7 | 1.45 |
| Ohmic response | 9 | 1.5 |
| Ohmic response | 9.3 | 1.55 |
| Ohmic response | 9.6 | 1.6 |
| Ohmic response | 9.9 | 1.65 |
| Ohmic response | 10.2 | 1.7 |
| Ohmic response | 10.5 | 1.75 |
| Ohmic response | 10.8 | 1.8 |
| Ohmic response | 11.1 | 1.85 |
| Ohmic response | 11.4 | 1.9 |
| Ohmic response | 11.7 | 1.95 |
| Ohmic response | 12 | 2 |
| Ohmic response | 12.3 | 2.05 |
| Ohmic response | 12.6 | 2.1 |
| Ohmic response | 12.9 | 2.15 |
| Ohmic response | 13.2 | 2.2 |
| Ohmic response | 13.5 | 2.25 |
| Ohmic response | 13.8 | 2.3 |
| Ohmic response | 14.1 | 2.35 |
| Ohmic response | 14.4 | 2.4 |
| Ohmic response | 14.7 | 2.45 |
| Ohmic response | 15 | 2.5 |
| Ohmic response | 15.3 | 2.55 |
| Ohmic response | 15.6 | 2.6 |
| Ohmic response | 15.9 | 2.65 |
| Ohmic response | 16.2 | 2.7 |
| Ohmic response | 16.5 | 2.75 |
| Ohmic response | 16.8 | 2.8 |
| Ohmic response | 17.1 | 2.85 |
| Ohmic response | 17.4 | 2.9 |
| Ohmic response | 17.7 | 2.95 |
| Ohmic response | 18 | 3 |
| Ohmic response | 18.3 | 3.05 |
| Ohmic response | 18.6 | 3.1 |
| Ohmic response | 18.9 | 3.15 |
| Ohmic response | 19.2 | 3.2 |
| Ohmic response | 19.5 | 3.25 |
| Ohmic response | 19.8 | 3.3 |
| Ohmic response | 20.1 | 3.35 |
| Ohmic response | 20.4 | 3.4 |
| Ohmic response | 20.7 | 3.45 |
| Ohmic response | 21 | 3.5 |
| Ohmic response | 21.3 | 3.55 |
| Ohmic response | 21.6 | 3.6 |
| Ohmic response | 21.9 | 3.65 |
| Ohmic response | 22.2 | 3.7 |
| Ohmic response | 22.5 | 3.75 |
| Ohmic response | 22.8 | 3.8 |
| Ohmic response | 23.1 | 3.85 |
| Ohmic response | 23.4 | 3.9 |
| Ohmic response | 23.7 | 3.95 |
| Ohmic response | 24 | 4 |
| Operating point | 12 | 2 |
Save your place when you finish reading.
Original Lilerno example
An ideal 6 Ω resistor has 12 V across it. Find current and dissipated power.
I = V/R = 12/6 = 2 A.
P = VI = 12 × 2 = 24 W.
This is a paper model, not a component recommendation.
Test the model
Open learning, traceable sources
Work in this order. These links open the publisher’s material; free access does not always permit republication.
MIT OpenCourseWare
Start with: Lumped circuits, resistive networks and transients
Solve schematic problems before attempting any supervised low-voltage hardware.
Recall, then record
Close the explanation and answer these in your own words. Return tomorrow, then again later in the week.
Voltage across or current through?
What is the power sign convention?
Which component ratings are missing?
Draw a labelled ideal DC circuit and verify current and power balance entirely on paper.
Self-reported tasks, not an assessment of mastery or university credit. Reading a page does not complete a chapter.
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Open learning, traceable sources
Original Lilerno lessons and diagrams, supported by these references. Free access does not always permit republication. Links open the publisher’s material.
Lumped circuits, resistors, sources, transients and basic electronic devices. Study before electromechanical control.
CC BY-NC-SA 4.0 except separately credited material. Linked for external study, not reproduced. Some assigned textbooks/software require separate access.
Open source ↗Rights / publisher record ↗