📚 Topic Summary
Determining impedance using an oscilloscope involves analyzing the voltage and current waveforms of an AC circuit. Impedance ($Z$) is the total opposition a circuit presents to alternating current and is analogous to resistance in a DC circuit. By applying a known AC signal to a circuit and observing the resulting voltage and current waveforms on an oscilloscope, we can calculate the impedance. Key parameters to measure are the peak-to-peak voltage ($V_{pp}$), peak-to-peak current ($I_{pp}$), and the phase difference ($\phi$) between the voltage and current waveforms. The magnitude of the impedance is calculated using Ohm's Law for AC circuits: $|Z| = \frac{V}{I}$. The phase angle indicates whether the circuit is more inductive (voltage leads current) or capacitive (current leads voltage).
🧮 Part A: Vocabulary
Match the following terms with their definitions:
| Term |
Definition |
| 1. Impedance |
A. The difference in time between two waveforms |
| 2. Oscilloscope |
B. A measure of the opposition to alternating current |
| 3. Phase Shift |
C. A circuit element that stores energy in an electric field |
| 4. Capacitor |
D. A test instrument used to visualize electrical signals |
| 5. AC Signal |
E. An electrical signal that periodically reverses direction |
✍️ Part B: Fill in the Blanks
An __________ displays voltage signals as a function of time. __________ is the opposition to the flow of __________ current. The impedance can be calculated by measuring the __________ and __________ and the __________ between them. A positive phase shift indicates a __________ circuit, while a negative phase shift indicates a __________ circuit.
🤔 Part C: Critical Thinking
Explain how you would use an oscilloscope to determine if a circuit is predominantly capacitive or inductive. What specific measurements would you take and how would you interpret them?