What Is a Switching Diode?
Switching diodes are fundamental electronic components, akin to transistors and ICs, and are categorized as active components. In contrast, resistors and capacitors are referred to as passive components.
These diodes are fabricated from semiconductors such as silicon, germanium, and gallium arsenide.
Diodes generally function to maintain a steady current and voltage, and they allow current to flow only in a predetermined direction.
Switching diodes are characterized by their brief switching time, the period needed to switch from a state of conduction, where current flows in one direction, to an interrupt state when the current’s direction is reversed.
Uses of Switching Diodes
In electronic circuits, switching diodes perform two main roles:
- Rectification
AC current is supplied from a commercial power source, whereas control circuits in electronic devices are designed for DC.
The unidirectional current conduction property of silicon diodes is utilized to convert AC to DC, a process termed rectification. - Detection
Silicon diodes are capable of wave detection, which involves extracting video and audio signals from broadcast radio waves, such as those in TV and radio.
Among various diode functions, switching diodes are specifically employed for rectifying and detecting small signals. They are not designed to manage large current flows in power supply circuits.
Principles of Switching Diodes
Diodes, such as transistors and ICs, are semiconductors, which share properties of conductors, like metals, and insulators, like plastics.
Metals efficiently conduct current due to the mobility of electrons as free carriers. Application of voltage to metals leads to the flow of electric current carried by these free electrons.
Semiconductors, however, can function as both conductors and insulators, depending on the applied current’s state.
P-type and N-type semiconductors differ in how they facilitate current flow. P-type semiconductors, positively charged due to a lack of electrons, rely on electron movement to fill ‘holes,’ while N-type semiconductors, negatively charged with surplus electrons, utilize these free electrons to conduct current.
Switching diodes, formed by combining P-type and N-type semiconductors, are recognized for their fast-switching times and small size, making them ideal for small-signal processing applications.