Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G7B
G7B09G7B

What determines the frequency of an LC oscillator?

Deep Dive: G7B09

The correct answer is C: The inductance and capacitance in the tank circuit. What determines the frequency of an LC oscillator is the inductance and capacitance in the tank circuit. The resonant frequency is f = 1/(2π√LC). For amateur radio operators, this is fundamental oscillator theory. Understanding this helps when designing oscillators.

Why Other Answers Are Wrong

Option A: Incorrect. Counter stages don't determine LC oscillator frequency - counters are for digital circuits, not LC oscillators. Counter stages aren't relevant. Option B: Incorrect. Divider stages don't determine LC oscillator frequency - dividers reduce frequency, not determine it. Divider stages aren't relevant. Option D: Incorrect. Time delay of lag circuit doesn't determine LC oscillator frequency - LC oscillators use tank circuits, not lag circuits. Lag circuits aren't relevant.

Exam Tip

LC oscillator frequency = inductance and capacitance in tank circuit. Think 'L'C 'O'scillator = 'L' and 'C' determine frequency. Resonant frequency f = 1/(2π√LC) depends on L and C values. Not counter stages, not divider stages, not lag circuit - just L and C.

Memory Aid

LC oscillator frequency = inductance and capacitance in tank circuit. Think 'L'C 'O'scillator = 'L' and 'C' determine frequency. Resonant frequency f = 1/(2π√LC) depends on L and C. Fundamental oscillator theory.

Real-World Example

An LC oscillator: The tank circuit has 10 µH inductance and 100 pF capacitance. Frequency = 1/(2π√(10×10⁻⁶ × 100×10⁻¹²)) = 5.03 MHz. The inductance and capacitance in the tank circuit determine the oscillator frequency. This is fundamental LC oscillator theory.

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G7B

Reference: 2023-2027 Question Pool · G7 - Practical Circuits

Key Concepts

LC oscillator Frequency determination Inductance and capacitance Tank circuit

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G7B topic.