Circuit labs for physics: Ohm’s law, series and parallel, RC
Mokxi is a free circuit simulator for physics labs that runs in a browser tab: a bench supply, resistors, capacitors, a multimeter and a two-channel scope. Students predict a voltage, measure it, change one part and predict again, every student at once.
Where Mokxi fits
The circuits unit of an introductory physics course, of AP Physics 2 and of AP Physics C: Electricity and Magnetism is Ohm’s law, series and parallel resistors, Kirchhoff’s laws, power, and capacitors charging through a resistor. Each one is a circuit students can build, measure and change here.
The analog parts are solved as a real circuit by nodal analysis, so a meter reads what the circuit does, including the effect of every other part on the node, not an idealized textbook answer.
The scope turns the RC time constant into a measurement. On the RC time constant page, a square wave drives 10 k into 100 nF, so the time constant is 1 millisecond, and students read the 63 percent point off the trace and compare it with R times C.
The labs, by topic
Each row is a topic, the week of the 12-week course that covers it, a circuit that runs now and the pages that explain it.
| Topic | Course week | Lab to open | Read more |
|---|---|---|---|
| Ohm’s law and the voltage divider | Week 1 | A divider, measured | Ohm's Law, in a Circuit You Can Run · Voltage Dividers and Why They Are Bad Power Supplies · How to Use a Multimeter: Practice on a Virtual One |
| Series and parallel resistors | Week 1 | The circuit on the reading page | Series vs Parallel Circuits, Seen With LEDs |
| The RC time constant | Week 4 | The circuit on the reading page | The RC Time Constant, on an Oscilloscope |
| An RC low pass and its corner frequency | Extra lab | RC filter on the scope | The RC Time Constant, on an Oscilloscope |
| RC filters and phase, on the bench | Extra lab | RC filter on the bench | Measure It: Read a Circuit With a Scope and Plotter |
| RL circuits | Extra lab | RL filter on the scope | |
| RLC resonance | Extra lab | RLC resonance on the bench |
Every week has a one-page PDF lesson plan. They are all on the teacher resources page.
Where it does not fit
- Mokxi solves circuits, not fields. There is no electric field, Gauss’s law, magnetic field or induction from a moving magnet.
- It runs SPICE decks on an engine checked against ngspice on 42 benchmark circuits. For a college course that needs manufacturers’ model libraries, distortion or Monte Carlo analysis, LTspice or ngspice goes further; the comparison page lists what Mokxi reads, runs and exports.
- Students should still use a real meter on a real resistor. The simulator gets them there knowing what to expect.
Standards this course touches
Mokxi is not certified against any of these. The rows below are the ones this course’s labs genuinely touch, taken from the full map on the teacher resources page.
| Standard | What it asks | Fit | Where Mokxi fits |
|---|---|---|---|
| NGSS HS-PS3-3 | Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy. | Partial fit | The design and refine steps: students design circuits that turn electrical energy into light, sound or motion (an LED, a buzzer, a motor) and test them before building. The build itself is physical, and a simulator does not replace it. |
| AP Physics 2 Unit 11 | Electric Circuits (the College Board unit title). | Good fit | Resistor networks, Kirchhoff’s laws, power and RC circuits, measured with a meter and a scope: week 1, week 4, and the Ohm’s law, series and parallel, and RC time constant pages. |
| AP Physics C: E&M Unit 11 | Electric Circuits (the College Board unit title). | Good fit | The same circuits as above. The RC charging curve is on the scope to measure; the calculus that predicts it is the student’s. |
| AP Physics C: E&M Unit 10 | Conductors and Capacitors (the College Board unit title). | Partial fit | Capacitors in circuits: charging, discharging, and series and parallel capacitance. Not fields, dielectrics or charge on conductors. |
| AP Physics C: E&M Unit 13 | Electromagnetic Induction (the College Board unit title). | Partial fit | RL and RLC circuits only, on the scope (the RL filter and RLC resonance projects). Not induction from a changing magnetic field. |
States adopt these frameworks with their own edits, and some use their own (Texas uses the TEKS, for example). Check the wording in your state’s document. If you send us a unit, we will tell you which weeks cover it and which do not.
Wording from: NGSS: HS-PS3-3 · NGSS: HS-ETS1 Engineering Design · NGSS: MS-ETS1-4 · CSTA K-12 Computer Science Standards · College Board: AP Physics 2 course page · College Board: AP Physics C: Electricity and Magnetism course page
More for this course
A free circuit simulator for high school · Science Olympiad Circuit Lab · The oscilloscope and meters · Mokxi and LTspice, compared · All the free teacher resources · The 12-week course · IT setup for schools
Other course pages: High school engineering and CTE: digital electronics · Middle school STEM: first circuits