Electrical Circuits Flashcards
6 cards from real EIT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Electrical Circuits flashcards as text
In an AC circuit, inductive reactance X_L is calculated as:
Answer: 2πfL
Inductive reactance X_L = 2πfL = ωL, where f is frequency and L is inductance in henries.
What theorem states that any linear two-terminal circuit can be replaced by a single voltage source and series resistance?
Answer: Thevenin's Theorem
Thevenin's Theorem simplifies complex networks to a voltage source V_th in series with resistance R_th.
At resonance in a series RLC circuit, the impedance is:
Answer: Minimum (equal to R)
At resonance, inductive and capacitive reactances cancel (X_L = X_C), leaving only resistance, so Z is minimum and equal to R.
What is the phase relationship between voltage and current in a pure inductor?
Answer: Voltage leads current by 90°
In a pure inductor, voltage leads current by 90° (π/2 radians) because V = L(dI/dt).
The turns ratio of a transformer is 10:1 (primary:secondary). If the primary voltage is 120V, what is the secondary voltage?
Answer: 12 V
V_s/V_p = N_s/N_p → V_s = 120 × (1/10) = 12 V.
Which circuit element opposes changes in voltage?
Answer: Capacitor
A capacitor stores energy in an electric field and opposes changes in voltage because V = Q/C and charge takes time to accumulate.