A Gunn diode oscillator takes advantage of which effect?

The Gunn diode oscillator operates primarily based on the concepts of negative resistance and bulk-effect phenomena.

Negative resistance is crucial for the functioning of a Gunn diode because it allows the diode to sustain oscillations. In certain conditions, the Gunn diode exhibits a region in its current-voltage characteristic where an increase in voltage leads to a decrease in current. This behavior is essential for generating oscillations because it provides the necessary conditions to amplify signals. As the diode switches between different states, the negative resistance enables it to maintain oscillatory action.

The bulk-effect refers to the material properties of the semiconductor used in Gunn diodes, which is typically gallium arsenide. This effect contributes to the establishment of high-frequency operation and influences the transit time of charge carriers within the diode. The interaction of these charge carriers and the bulk material properties lead to the generation of oscillations at microwave frequencies.

Thus, the correct answer encompasses both negative resistance and the bulk-effect as integral mechanisms that enable the Gunn diode oscillator to function effectively.