värähtelypiirissä

Värähtelypiiri, often translated as resonant circuit or oscillating circuit, is a fundamental electronic circuit composed of inductance and capacitance. Its primary function is to store and release electrical energy rhythmically, leading to oscillations at a specific frequency. The natural frequency of oscillation, also known as the resonant frequency, is determined by the values of the inductor (L) and capacitor (C) according to the formula f = 1 / (2π√(LC)).

When a voltage is applied to a capacitor, it stores electrical charge. This charge can then flow through an inductor, generating a magnetic field. As the capacitor discharges, the magnetic field in the inductor collapses, inducing a voltage that recharges the capacitor, but with opposite polarity. This process repeats, causing the circuit to oscillate. In an ideal, lossless circuit, these oscillations would continue indefinitely.

In real-world circuits, energy is lost due to resistance, either inherent in the inductor and capacitor or added externally. This damping causes the amplitude of the oscillations to decrease over time. To sustain oscillations, an external energy source and a mechanism for amplification are required, forming what is known as an active or driven oscillator.

Värähtelypiiri circuits are ubiquitous in electronics. They are essential components in radio transmitters and receivers for tuning to specific frequencies, in signal generators for creating test signals, and in many other applications where precise frequency control is necessary, such as in timing circuits and electronic musical instruments. The ability to select and amplify specific frequencies is their key characteristic.