| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the impedance of the circuit.
Tip: Place the measurement results in the (I, U) coordinate system.
Answer: $32\ \Omega$