What electronic component can be affected by changes in DC voltage to adjust frequency in oscillators?

The varactor, also known as a varicap or voltage-controlled capacitor, is the electronic component that can be influenced by changes in DC voltage to adjust frequency in oscillators. This type of capacitor relies on the concept that its capacitance value varies with the applied DC voltage. As the voltage across the varactor changes, it alters the depletion region within the semiconductor material, which in turn changes the capacitance.

In oscillator circuits, this variable capacitance allows for fine-tuning of the frequency of oscillation. By varying the DC voltage, the frequency can be easily adjusted, making varactors integral in applications such as voltage-controlled oscillators (VCOs) and phase-locked loops (PLLs), where precise control of frequency is essential.

The other components listed – inductors, diodes, and transformers – do not function in the same manner as varactors when it comes to frequency adjustment through changes in DC voltage. Inductors have a defined inductance that depends on physical characteristics and does not vary with DC voltage in a way that aids frequency modulation. Diodes can rectify and switch, but they do not primarily serve the purpose of frequency adjustment in oscillators. Lastly, transformers are used for electrical isolation and voltage transformation, but they