ARRL Technician Practice Exam

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Prepare for the ARRL Technician Exam. Access flashcards and multiple choice questions with detailed explanations. Get ready to become a certified amateur radio operator!

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What electronic component allows current to flow in only one direction?

Transistor
Capacitor
Diode
Inductor

The correct answer is: Diode

The correct answer is the diode. A diode is a semiconductor device that is specifically designed to allow current to flow in only one direction. This property is essential in various applications, such as rectification, where alternating current (AC) must be converted into direct current (DC). The construction of a diode typically includes a p-n junction, which creates a barrier that permits electron flow from the n-type material to the p-type material while blocking it in the reverse direction. This unidirectional conductivity makes diodes integral to circuits requiring current control and prevents damage from reverse polarity. In contrast, transistors are used for amplification and switching, and they can control current flow but do not restrict it to a single direction like diodes do. Capacitors store and release electrical energy but do not direct the flow of current in any specific direction. Inductors store energy in a magnetic field and also do not restrict current flow directionally. Hence, while these components have their unique roles in electronic circuits, it is the diode that uniquely performs the function of allowing electric current to flow in one direction only.