In a circuit, how does a diode operate?

A diode is a semiconductor device that is designed to allow current to flow primarily in one direction. This unidirectional flow is made possible by the diode's construction, which typically consists of a p-n junction. When the diode is forward-biased, meaning that the positive side (anode) is connected to a higher voltage than the negative side (cathode), it permits the flow of electric current. Conversely, when the diode is reverse-biased, with the anode at a lower voltage than the cathode, it effectively blocks current from flowing. This property is crucial in many electronic applications, such as rectification, where alternating current (AC) is converted to direct current (DC).

The other options misrepresent the fundamental function of a diode. Allowing current to flow in both directions overlooks the primary characteristic of a diode and is a feature associated with components like resistors in some situations. Suggesting that the diode only allows alternating current to pass is incorrect, as diodes are designed to control the direction of current flow irrespective of the current type. Lastly, stating that a diode amplifies the electrical signal confuses diodes with transistors, which are the components used for signal amplification in circuits. Thus, option B accurately represents the