Understanding Electronics: Components, Current, and More
Understanding Electronics: Components and Principles
Electronics is the science and technology that deals with the study of electrons and their applications in the processing and transmission of information.
Early Electronic Components: Vacuum Valves
Thermionic vacuum valves are considered the first electronic component. New findings were encouraging, leading to the development of radio, television, radar, and control systems. This culminated in the construction of the first computer (called ENIAC) in 1941. Starting in 1948, vacuum valves began to be replaced by diodes and transistors manufactured using semiconductor materials such as silicon or germanium.
Direct Current (DC)
DC is characterized by the fact that the movement of electrons is always in the same direction, with a constant voltage and current over time.
Alternating Current (AC)
Instead, AC is distinguished by being a variable current in which the main figures that define it—voltage and current—continually update in value and meaning.
Passive Electronic Components
Passive electronic components are those that, alone, are unable to generate or amplify electrical signals. They act as a load, reducing or adjusting the electrical signal of the circuit.
Active Electronic Components
Active electronic components, however, are able to generate, modify, and amplify the value of the electrical signal.
Resistors
Resistors are passive components that provide a certain resistance to the passage of electric current.
Rheostats and Potentiometers
Rheostats and potentiometers are variable resistors that can be manually adjusted. They serve, for example, to vary the volume of a music device, the intensity of a light bulb, or an engine speed.
Light Dependent Resistors (LDR)
An LDR is a resistor responsive to the intensity of light it receives. Therefore, its resistance varies with the light that passes through it; the more light, the less resistance.
Negative Temperature Coefficient (NTC) Resistors
An NTC resistor varies with heat and has a negative temperature coefficient. This means that as temperature increases, resistance decreases.
Positive Temperature Coefficient (PTC) Resistors
The PTC resistor behaves contrary to NTC; its resistance increases with increasing temperature.
Capacitors
The capacitor is a component that serves to temporarily store electrical charges in a relatively small area.
The storage capacity of a capacitor, which is the relationship between electric charge and the potential difference it acquires, is measured in farads (F) in the International System (SI). Because this is a very high unit value, submultiples are used in practice.
Relays
The relay is an electric switch that is activated by an electromagnet. It consists of a coil that, when an electric current circulates, attracts a sheet metal which operates a contact, which opens or closes.
Diodes
Diodes are active electronic components that allow the passage of current in one direction. It has two terminals, called the anode (area D) and cathode (area N). When in this state, the diode is polarized and can conduct, behaving like a closed switch.
Light Emitting Diodes (LED)
The LED is an electronic component that emits light when an electric current is passed through it.
Transistors
The transistor is an electronic component composed of semiconductor material that comprises three distinct sections: emitter (E), base (B), and collector (C). The combination of these parts of class P or N semiconductor gives rise to two types of transistors: the NPN transistor and the PNP transistor.
Linear mode transistor operation is characterized by the intensity and tension output (collector-emitter), and the intensities are a function of input voltages (base-emitter), which can take many values and points of operation.