Electrical Circuits
Learn DC and AC circuit analysis, power factor and three-phase basics, safe measurement on battery circuits, simulation, transformers, motors and systematic troubleshooting.
Leads to: Electrical Engineer, Physicist, Electrician, Industrial Machinery Mechanic
Before you start
This course builds on Math for Tech & STEM. Take it first if you are new to the topic.
About this course
An intermediate course for future electricians, electrical engineers, physicists and industrial maintenance mechanics. You will relate voltage, current, resistance and power with Ohm's law; reduce series-parallel networks; solve a two-loop circuit with Kirchhoff's laws; describe AC waveforms with peak, RMS, frequency and period; compute reactance and impedance; work out real, reactive and apparent power and the basics of three-phase systems; use a multimeter safely on battery circuits; build and measure an LED circuit on a breadboard; simulate circuits in a free browser simulator; size transformer voltages and currents from the turns ratio; compare DC and AC induction motors; and find faults with a systematic test plan. The only prerequisite is Math for Tech & STEM: the code activities are small fill-in-the-blank calculators with one formula to write, and no programming course is needed. Every hands-on task uses batteries of 9 V or less, paper or a simulator. Never practise on mains wiring: working on real installations requires employer or school training, supervision and, for electricians, an apprenticeship and licence.
Course content
Module 1
DC Circuits
3 lessons · 2h 45mVoltage, current, resistance and power; series and parallel networks; and Kirchhoff's laws for multi-loop circuits.
- 54mVoltage, current, resistance, powerReading
Relate voltage, current, resistance and power with Ohm's law and the power formula.
- 1h 2mSeries and parallelReading
Solve series, parallel and series-parallel resistor networks for total resistance, current and voltage.
- 49mKirchhoff's lawsReading
Use Kirchhoff's current and voltage laws and mesh analysis to solve a two-loop circuit.
Module 2
AC Circuits
3 lessons · 1h 46mAC waveforms and RMS values, reactance and impedance, power factor and the basics of three-phase power.
- 32mAC waveformsReading
Describe a sine wave with peak, peak-to-peak, RMS, frequency and period, and convert between them.
- 40mInductors, capacitors, impedanceReading
Compute inductive and capacitive reactance and the impedance of a series R-L-C circuit at a given frequency.
- 34mPower factor and three-phaseReading
Compute real, reactive and apparent power, power factor, and balanced three-phase loads.
Module 3
Measurement and Safety
3 lessons · 2h 19mUsing a multimeter safely, building and measuring a battery LED circuit on a breadboard, and simulating circuits in a free tool.
- 1h 1mUsing a multimeterReading
Measure voltage, resistance, continuity and current safely on battery-powered circuits.
- 40mBreadboard circuitsReading
Size a resistor for an LED, build the circuit on a breadboard and check it with your meter.
- 38mCircuit simulationReading
Build, measure and break circuits safely in a free browser simulator.
Module 4
Motors and Transformers
3 lessons · 1h 53mTransformer turns ratios, how DC and AC induction motors work, and a systematic method for finding circuit faults.
- 40mTransformersReading
Use the turns ratio to compute transformer secondary voltage, primary and secondary current, and a VA rating.
- 34mMotorsReading
Compare how DC motors and AC induction motors work, how their speed is controlled and how they fail.
- 39mTroubleshooting circuitsReading
Find opens, shorts and high-resistance faults with a systematic, written test plan.