PLC Simulator

Industrial electrical basics for controls and maintenance work

The electrics you need before PLC wiring: Ohm's law to a start/stop circuit, in 12 short units.

12 units
4 free
2.8 hours
Start free: Voltage, current, resistance and powerSee plans

Training material. Follow your site procedures, local electrical code and the manufacturer's instructions. Lockout/tagout and a qualified person are required for real equipment.

What you will be able to do

  • Calculate voltage, current, resistance and power for simple circuits and explain why current heats cables.
  • Tell series from parallel circuits and predict what one open device does.
  • Read a simple schematic and identify supply, fuse, switch, relay coil and contact, lamp and motor symbols.
  • Choose between 24 V DC and mains control power and compare the current each needs.
  • Read a motor nameplate, explain line and phase voltage, and recognise phase loss and reversed rotation.
  • Read a three-wire start/stop circuit and predict what each device does when it operates or fails.

  1. 01

    Voltage, current, resistance and power

    Free15 min · lesson

    Solve Ohm's law and the power equation from any two known values with a small playground, and see why current rather than voltage heats cables.

  2. 02

    Series and parallel circuits

    Free12 min · lesson

    Rewire a lamp bank between series and parallel, blow a lamp, and learn how current, voltage and resistance behave in each.

  3. 03

    Reading a simple schematic

    Free12 min · lesson

    Follow a current path on a drawing and click to identify the seven symbols you meet first.

  4. 04

    Control power: 24 V DC or mains

    Free10 min · lesson

    Compare the two supplies in one panel, work out the current each needs for the same power, and see why plants keep both.

  5. 05

    Meters done safely

    Pro15 min · lesson

    Match meter mode to question, learn why continuity and resistance are for dead circuits only, and read a voltage pattern to find an open part.

  6. 06

    Relays and contactors

    Pro12 min · lesson

    Separate coil circuit from contact circuit, work through NO and NC with a coil demo, and see how a tiny coil current switches a larger load.

  7. 07

    Motors: single-phase, three-phase and the nameplate

    Pro15 min · lesson

    Read a motor nameplate line by line to choose star or delta, find the protection current, and estimate speed and efficiency.

  8. 08

    Three-phase basics

    Pro15 min · lesson

    Relate line and phase voltage, estimate line current for a balanced load, and see what swapped conductors or a lost phase do to a motor.

  9. 09

    Overload protection: fuses and breakers

    Pro15 min · lesson

    Learn what a fuse, breaker and overload relay each protect, and how a conceptual trip curve separates overload from short circuit.

  10. 10

    Grounding and bonding

    Pro12 min · lesson

    See why the protective earth exists and what a live-to-frame fault does with and without a low-resistance earth path.

  11. 11

    Voltage drop and wire gauge

    Pro15 min · lesson

    Estimate the voltage a copper cable loses from length, size and current, and see why long 24 V runs need thicker conductors.

  12. 12

    Capstone: read a three-wire start/stop circuit

    Pro20 min · lesson

    Read the standard motor start and stop control circuit, operate each device in a simulator, and answer graded prediction questions.

Who this track is for

Newcomers to plant electrics heading into PLC, panel wiring and maintenance work, who need the basics in plain language first.

4 of the 12 units are free with a free account, with no card and no expiry. The other 8 are part of a paid plan; compare them on the pricing page.

Related tracks

What is the difference between a relay and a contactor?

Both are electrically operated switches. A relay switches small control currents, usually in a control circuit. A contactor is built to make and break motor-level power repeatedly, with heavier contacts and arc handling. In a motor starter the relay-style control circuit tells the contactor when to close.

What electrical knowledge do I need before learning PLCs?

You need to know what a control circuit is, how a normally open and a normally closed contact behave, and why a stop button is wired the way it is. A PLC program is a software version of that relay logic, so the electrical picture makes the ladder diagram obvious instead of mysterious.

Is this a replacement for an electrician apprenticeship or licence?

No. It is training material for understanding control circuits. Follow your site procedures, local electrical code and the manufacturer instructions, and use a qualified person with lockout/tagout for any real equipment.

How much of Electrical Foundations is free?

4 of the 12 units are free with a free account, no credit card and no expiry, starting with Voltage, current, resistance and power. The remaining 8 units are included with a paid plan; see the pricing page for the current plans.

Do I need a PLC or any hardware?

No. Everything runs in the browser against simulated equipment. It is training material: it does not replace supervised practice on real equipment, and lockout/tagout and a qualified person are required for real equipment.

Start with the free units

Browser-based, no install, no hardware.

Start free: Voltage, current, resistance and power