Which statement describes the operation of a series-fed Hartley oscillator?

The statement regarding the operation of a series-fed Hartley oscillator is accurately captured by the assertion that it is series fed because DC flows through the tank. In a series-fed Hartley oscillator, the oscillation circuit consists of an inductor-capacitor (LC) tank circuit, which is integrated into the feedback path and is powered by a DC supply. This DC voltage is necessary to bias the active device, usually a transistor, allowing it to operate in the active region where it can amplify signals.

The operation of a series-fed configuration means that the tank circuit is connected in series with the power supply, allowing for the necessary DC voltage to be applied to the oscillator while the LC components resonate at a particular frequency, producing an AC signal (the oscillation). The tank circuit's resonance is pivotal as it establishes the frequency of oscillation.

In contrast, options that mention solely AC power sources or feedback resistors do not accurately reflect the fundamental operational principles of a series-fed Hartley oscillator, since it fundamentally relies on DC power to initiate and stabilize oscillations. Moreover, while oscillators can produce various waveforms, the Hartley oscillator typically generates sinusoidal outputs rather than square waves. Thus, the structure and operation of the Hartley oscillator clearly align