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Measurement prep voltmeter, ammeter and Kirchhoff's laws

Prepare your lab sessions: connect and read voltmeter, ammeter, ohmmeter and wattmeter, real generators and Kirchhoff's laws. 4 steps · 64 levels · before practical lab sessions

First levelStep 1 · The voltmeterConnecting instruments, level 1 of 6
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The 4 steps each step unlocks the next

  1. 1

    1. Connecting instruments

    6 levelsLesson: Voltmeter and ammeter

    Voltmeter in parallel, ammeter in series, potentiometer, classic mistakes.

    1. 1The voltmeter
    2. 2Voltmeter on R2
    3. 3Ammeter in series
    4. 4Measure, then conclude
    5. 5Connecting a voltmeter
    6. 6Connecting an ammeter
  2. 2

    2. Reading and choosing

    10 levelsLesson: Voltmeter and ammeter

    Ranges, needle dials, ohmmeter, wattmeter, internal resistance of meters, shunt.

    1. 1Reading a needle voltmeter
    2. 2Reading a needle ammeter
    3. 3Choosing the range
    4. 4Range and needle
    5. 5Ohmmeter rule
    6. 6Measuring a resistance with an ohmmeter
    7. 7Reading a wattmeter
    8. 8Not-so-perfect voltmeter
    9. 9Upstream or downstream connection
    10. 10Shunt calculation
  3. 3

    3. Real generators

    36 levelsLesson: EMF and internal resistance

    E, r, E', r' and plotting the U = f(I) characteristic.

    1. 1Generator in opposition
    2. 2Real generator
    3. 3EMF of an accumulator cell
    4. 4Current delivered by an accumulator
    5. 5External resistance of an accumulator
    6. 6Predict the current of a real cell
    7. 7Voltage needed to recharge an accumulator
    8. 8Maximum charging current
    9. 9EMF of a charging accumulator
    10. 10A cell and its load
    11. 11Internal resistance of an accumulator
    12. 12Ammeter connected straight across a cell
    13. 13Electrical efficiency of a generator
    14. 14Measure the internal resistance of a cell
    15. 15No load, then under load
    16. 16Internal resistance of a charging accumulator
    17. 17Battery of n cells being charged
    18. 18Useful power of a motor
    19. 19Predict the current of a motor
    20. 20Measure the back-EMF of a motor
    21. 21Get the wanted current in a motor
    22. 22Accumulator being charged
    23. 23Two accumulators in opposition
    24. 24Limiting the charging current
    25. 25Rheostat between a generator and a load
    26. 26Two cells in opposition
    27. 27Current drawn by a motor
    28. 28Generalised Ohm's law
    29. 29Active load
    30. 30Voltage under load
    31. 31Load for a given efficiency
    32. 32Generalised Ohm's law: missing EMF
    33. 33Two cells, one motor, two resistors
    34. 34Set the rheostat of a motor
    35. 35Plotting U = f(I)
    36. 36Internal resistance from the slope
  4. 4

    4. Kirchhoff's laws

    12 levelsLesson: Kirchhoff's current and voltage laws

    Junctions, loops, several sources, Wheatstone bridge.

    1. 1Junction rule
    2. 2Current at the junction
    3. 3Two cells in series
    4. 4Missing current
    5. 5Which branch carries the most current?
    6. 6Junction law in the lab
    7. 7Cells in opposition
    8. 8Loop equation
    9. 9Two sources, three branches
    10. 10Two sources on one load
    11. 11Two-source ladder
    12. 12Reproduce a bridge

Who is it for?

  • AudienceConnecting and reading the instruments, to prepare lab sessions.
  • Pacebefore practical lab sessions
  • HelpA hint, then the full working, for every problem.
  • EquipmentA browser is enough; the lab is more comfortable on a large screen.

Frequently asked questions about this path

Are there any prerequisites?

The first steps go over the basics; if you're a complete beginner, start with the Discovery path.

Can I skip a step?

Steps unlock in order, but all lessons and all problems remain freely available from the lessons.

Where is my progress saved?

In the device's browser; with a free account, it follows you from one device to another.

Other learning paths

Simulated time00:00:00
Q = I·t-
W = P·t-

Circuit diagram CEI 60617

How does it work?

Each big hole is a circuit node: you push one leg of a component into it. The 4 small holes around it are connected to it: chips and leads plug in there.

  1. Place a component Drag it from the palette: it snaps onto the grid. R rotates it.
  2. Bridge neighbouring holes Pick the jumper chip (or C) and drag on the board: bridged holes become a single node.
  3. Draw a lead For long links and the power supply: from one big hole to another, or to a terminal.
  4. Close the loop The circuit is solved live (Ohm, Kirchhoff) and the diagram follows.

Shortcuts

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C
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