Electronic Components: Integrated Circuits, Coils, Transformers, and More

Posted on Dec 12, 2024 in Electronics

Integrated Circuits (ICs)

An integrated circuit (IC) is a compact semiconductor device, typically a few square millimeters in size. Electronic circuits are fabricated on this semiconductor material, usually via photolithography. The IC is housed within a protective plastic or ceramic package. This package includes the necessary hardware connections to link the chip to a printed circuit board.

Types of Integrated Circuits

Integrated circuits are categorized into three main types:

  • Monolithic Circuits: These are fabricated on a single crystal, commonly silicon. Other materials like germanium, gallium arsenide, and silicon-germanium are also used.
  • Thin-Film Hybrid Circuits: Similar to monolithic circuits, these also incorporate components that are challenging to produce using monolithic technology. Many analog-to-digital (A/D) and digital-to-analog (D/A) converters were made using hybrid technology until advancements allowed for precise resistance fabrication.
  • Thick-Film Hybrid Circuits: These differ significantly from monolithic circuits. They often include unpackaged monolithic circuits, transistors, diodes, etc., on a dielectric substrate, interconnected by conductive traces. Resistors are applied via screen printing, and adjustments are made using laser trimming. The assembly is encapsulated in plastic or metal, depending on the required power dissipation. Some circuits use an epoxy resin for protection instead of a shaped capsule. Hybrid circuits are available for RF modules, power supplies, and power circuits.

Classification of Integrated Circuits

  • SSI (Small Scale Integration): 10 to 100 transistors
  • MSI (Medium Scale Integration): 101 to 1,000 transistors
  • LSI (Large Scale Integration): 1,001 to 10,000 transistors
  • VLSI (Very Large Scale Integration): 10,001 to 100,000 transistors
  • ULSI (Ultra Large Scale Integration): 100,001 to 1,000,000 transistors
  • GLSI (Giga Large Scale Integration): Over one million transistors

Coils

Coils are passive two-terminal components that produce a magnetic flux when an electric current flows through them. They are constructed by winding a wire around a core, which can be ferromagnetic or air. The unit of measurement for coils is the Henry (H), though submultiples like mH and μH are commonly used.

Types of Coils

1. Fixed Coils

Air Core

The conductor is wound around a support and then removed, leaving a spring-like appearance. These are used in high-frequency applications. A variation, the solenoid coil, features insulated coils and a base that doesn’t need to be cylindrical, suitable for many turns. These coils can have intermediate connections, effectively acting as multiple coils in series, and are used for high frequencies.

Solid Core

These coils have higher inductance values due to the high magnetic permeability of their cores, typically made of ferromagnetic materials like ferrite or Ferroxcube. For high power and low-frequency applications, cores similar to those in power converters are used, often with EI, M, UI, or L-shaped sections.

Honeycomb coils are used in radio tuner circuits for medium and long-wave ranges, achieving high inductance in a small volume. Toroidal core coils prevent magnetic flux leakage, offering high performance and accuracy. Ferrite coils, wound on a cylindrical ferrite core, are useful in radio applications, acting as antennas within the receiver.

Coils engraved on copper on a printed circuit board are cost-effective but challenging to adjust.

Transformers

A transformer is an electrical device that can either increase or decrease the voltage in an alternating current electrical circuit while maintaining the frequency. In an ideal transformer, the power input equals the output power. However, real transformers have a small percentage of losses, which vary based on design, size, and other factors.

Transformers operate based on electromagnetic induction. In their simplest form, they consist of two coils wound around a closed core made of iron or silicon-iron. These coils are termed primary and secondary, depending on whether they are the input or output of the system, respectively. Some transformers have an additional “third” winding, typically with a lower voltage than the secondary.

Transistors

The transistor is a semiconductor device used in electronics to function as an amplifier, oscillator, switch, or rectifier. The term “transistor” is derived from the English phrase “transfer resistor.” Transistors are ubiquitous in modern appliances, including radios, TVs, VCRs, audio and video players, microwave ovens, washing machines, automobiles, refrigeration equipment, alarms, quartz watches, computers, calculators, printers, fluorescent lamps, X-ray machines, CT scanners, ultrasound scanners, MP3 players, and cell phones.

Diodes

A diode (from the Greek for “two paths”) is a semiconductor device that permits electric current to flow in one direction, similar to a switch. The characteristic curve (I-V) of a diode typically shows two regions: below a certain potential difference.

Electrical Switches

An electrical switch is a device that redirects or interrupts the flow of electrical current. In the modern world, switches have numerous applications, from simple switches that turn a light bulb on or off to complex automatic transfer switches controlled by multi-layered computers.

In its most basic form, a switch consists of two metal contacts and an actuator. The contacts, normally separated, are brought together to allow current flow. The actuator is the movable part that applies pressure to keep the contacts together.

Classification of Switches

Push Buttons

Also known as a momentary switch, this type requires the operator to maintain pressure on the actuator to keep the contacts connected. An example is a doorbell.

Number of Poles

This refers to the number of individual circuits a switch controls. A single-pole switch can turn on a lamp. Switches can have two or more poles. For instance, to turn on a 220 volt motor and a 12-volt LED, a two-pole switch is needed, one for each voltage circuit.

Number of Channels

This is the number of positions a switch has. A one-way switch turns a lamp on in one position and off in the other.

There can be two or more channels. A three-way switch could control a traffic light, with each position turning on a different colored bulb.

Combinations

The above classifications can be combined to create various switch types. For example, a DPDT switch combines these features.

Electrical Resistance

Electrical resistance, often denoted as R, is the difficulty or opposition a body presents to the flow of an electric current. In the International System of Units, resistance is measured in ohms, represented by the Greek letter omega (Ω). Various methods, including using an ohmmeter, can measure resistance.

This definition applies to both direct current (DC) and alternating current (AC) for purely resistive elements, without inductive or capacitive components. When reactive components are present, the opposition to current flow is termed impedance.

Based on their resistance, materials are classified as conductors, insulators, and semiconductors. Some materials exhibit superconductivity under specific temperature conditions, where resistance is nearly zero.

Capacitors

In electricity and electronics, a capacitor is a device that stores electrical energy. It is a passive component consisting of a pair of conductive surfaces positioned for total influence (where all electric field lines from one surface terminate on the other). These surfaces are typically in the form of plates or fields, separated by a dielectric material (which reduces the electric field by acting as an insulator) or a vacuum. When subjected to a potential difference, the capacitor stores an electric charge, with one plate becoming positive and the other negative, while the total charge remains zero.