Electronic Components & Circuit Analysis Flashcards

Two resistors of 6 kΩ and 3 kΩ are connected in parallel. What is the equivalent resistance?

Answer: 2 kΩ

Parallel resistance: 1/Req = 1/6k + 1/3k = 1/6k + 2/6k = 3/6k, so Req = 2 kΩ.

What is the impedance of a pure inductor at DC (0 Hz)?

Answer: Zero

Inductive reactance XL = 2πfL equals zero at DC (f = 0 Hz), so a pure inductor is a short circuit at DC.

In a BJT, the current gain β (beta) is defined as:

Answer: IC / IB

Beta (β or hFE) is the ratio of collector current to base current, typically ranging from 20 to 500 for common transistors.

An electrolytic capacitor is installed with reversed polarity in a DC circuit. What will most likely occur?

Answer: It may overheat and fail catastrophically

Electrolytic capacitors are polarized; reverse polarity breaks down the oxide dielectric layer, causing excessive leakage current, heat, and possible explosion.

What is the resonant frequency of a circuit with L = 10 mH and C = 10 μF?

Answer: 503 Hz

fr = 1 / (2π√LC) = 1 / (2π√(0.01 × 0.00001)) = 1 / (2π × 3.16×10⁻⁴) ≈ 503 Hz.

Which diode characteristic curve region allows the diode to be used as a variable capacitor (varactor)?

Answer: Reverse bias region below breakdown

In the reverse-bias region, the depletion layer width varies with voltage, creating a voltage-controlled junction capacitance used in varactor (varicap) diodes.

Kirchhoff's Voltage Law (KVL) states that:

Answer: The algebraic sum of voltages around any closed loop equals zero

KVL states that the sum of all EMFs and voltage drops around any closed loop in a circuit equals zero, based on conservation of energy.