Key relationship
L=core multiplier × Lair; XL=2πfL; Z=√(R²+XL²); I=Vrms/Z.
Physics · Practical apparatus
Core-dependent coil impedance
Compare current with and without the core at the same RMS voltage and frequency. The core raises inductance in this linear guide, increasing reactance and reducing current. Measure V/I rather than mistaking it for DC resistance.
Open the interactive experiment →Core-dependent coil impedance
ஒரே AC மின்னழுத்தத்தில் இரும்புக் கரு இட்டால் தூண்டல் எதிர்ப்பு அதிகரித்து மின்னோட்டம் குறையும்.
Key notes, relationships and model limits
Practical tip
Compare current with and without the core at the same RMS voltage and frequency. The core raises inductance in this linear guide, increasing reactance and reducing current. Measure V/I rather than mistaking it for DC resistance.
Common trap
Inductance multiplier is an explicit approximation, not a full ferromagnetic model.
Model limits
Linear lumped coil; iron insertion represented by a constant inductance multiplier. Hysteresis, saturation and extra core losses omitted.
What you will learn
Infer impedance from virtual RMS meters and compare core effects.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
20 mH at50 Hz gives XL≈6.28 Ω; with10 Ω copper R, Z≈11.81 Ω.
Why this matters
The model connects core-dependent coil impedance with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
V/I in this AC coil measures?
- Only copper resistance
- Impedance
- Capacitance
Read the explanation
Voltage and current include both resistive and inductive effects.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.