In electronics, what is the function of a diode?

• A. Stores energy in magnetic field
• B. Limits current in one direction
• C. Amplifies electrical signals
• D. Converts AC to DC

Answer: (B)

A diode’s function is to allow current to flow primarily in one direction while blocking it in the opposite direction. This unidirectional behavior comes from the PN junction: when forward biased, the diode conducts; when reverse biased, it blocks. That makes diodes useful for controlling the direction of current, protecting circuits from reverse polarity, and serving in rectifier circuits to convert AC to DC in power supplies (though a single diode by itself doesn’t produce a steady DC without additional diodes and filtering). The other options describe roles for different components: storing energy in a magnetic field is the job of an inductor, amplifying signals requires an active device like a transistor, and converting AC to DC typically needs a rectifier arrangement rather than a single diode.