LCpiiri

LCpiiri, or LC circuit, is an electrical circuit composed of an inductor (L) and a capacitor (C) connected in series or in parallel. It is designed to resonate at a specific frequency, allowing selective response to signals near that frequency. The term is widely used in radio engineering and electronics.

The resonance frequency is f0 = 1/(2π sqrt(LC)). At this frequency, the reactive effects of the inductor and capacitor cancel each other, producing distinct impedance behavior. In a series LC circuit, the impedance is minimal at resonance, so the circuit can pass a signal with little attenuation. In a parallel LC circuit, the impedance is maximal at resonance, making the circuit highly selective or even acting as a band-pass or band-stop element when embedded in a larger network. In an ideal LC circuit, energy continuously exchanges between the magnetic field of the inductor and the electric field of the capacitor with negligible losses.

In real circuits, resistance and other parasitics introduce damping, giving a finite quality factor (Q). The Q factor, along with the circuit’s bandwidth, determines its selectivity. Tolerances of L and C values, temperature coefficients, and layout parasitics influence the actual resonance and stability.

LCpiire is used in a range of applications, including tuning circuits in radios, intermediate-frequency filters, and as tank circuits in oscillators and frequency synthesizers. Variants include the inclusion of a varactor for voltage-controlled tuning, or using a parallel or series configuration to achieve desired filtering or oscillation behavior.