Electronics Fundamentals for Dummies: Terms and Devices Used in Electrical Engineering

People begin to take an interest in electronics at any age and for a variety of reasons. Someone needs science for work or study, while for someone it just arouses interest. To get a complete understanding of this topic and understand its basic terms, you will need to study the basics of electronics and electrical engineering.

Basic concepts

During school years, everyone had to learn the basics of electronics in physics lessons. But because of the complex terms, the abundance of formulas and different units of measurement, not everyone was able to assimilate the information. There are different situations in life when a person needs this knowledge. Today there are many tutorials, publications and magazines that describe the basics of electronics. For beginners, these tutorials are good helpers., since all the basic concepts and processes in them are presented in an accessible language.

The most common terms from the field of electronics that people hear in everyday life are the words current, voltage and resistance. To understand their essence, you need to remember that any substance is a collection of positively and negatively charged particles (protons and electrons).

A directionally moving stream of electrons forms a current. The force that moves them in one direction is called stress. The movement of negative particles does not occur unimpeded, it is hindered by friction, which is called resistance in physics. These quantities are interrelated, so knowing two of them, you can easily calculate the third using the appropriate formula.

Each value in electronics has its own designation and is measured in specific units. Current A - in amperes, resistance R - in ohms, voltage U - in volts.

The use of electricity

The so-called electronics for "dummies" not only explains to beginners the nature of the occurrence of electric current, but also gives examples of its application. The range of voltage sources is very wide. They all have different sizes and specifications:

1. Lithium battery. Designed for a nominal load of 3 V. Due to its small size, it is well suited for use in pocket devices (watches, flashlights). It may have a capacity of 30-500 mAh.
2. Nickel metal hydride element. It is characterized by high energy density and fast charge storage capacity. It is often used to power various robotics.

The lead-acid battery is also a kind of power supply and occupies a special place among the known power sources. Its design consists of the following elements:

• positive and negative contact;
• a set of electrodes with different charges;
• safety and separating valve.

All parts are enclosed in a robust case. Such a battery is the main source of voltage for most electronic devices. It is easy and fast to recharge, well suited for systems in which the main role is played not by the weight of the device, but by its energy storage.

Specifications

Battery performance is influenced by the way it is connected. Serial connection leads to an increase in voltage, parallel - to an increase in current.

The main characteristic of an energy source in electronics is capacity. This value serves as a measure of the charge stored in it and directly depends on the mass of the active substance. By specifying the nominal capacity, manufacturers mean the maximum amount of electricity that can be extracted under specific conditions. But since the conditions for using batteries are far from ideal, in practice the capacity level is lower than stated. The main factors affecting its decrease are the duration of operation, temperature regime, the number of charges and discharges.

As a unit of measurement for this parameter, it is customary to use watt-hours (W * h), kilowatt-hours (kW * h), ampere-hours (A * h) or milliampere-hours (mA * h). A watt-hour is defined as the product of the current and the voltage produced by the device in one hour. The voltage level is constant and depends on what type of energy source belongs to (lithium, alkaline, lead-acid).

In the event of a complete discharge, most voltage sources fail. To prevent damage, manufacturers determine the proportion of current that can be drawn from it. This is called the depth of discharge and is measured as a percentage of the maximum capacity.

Electric current limiters

Some electronic devices require limiting the electrical current. To achieve this, a special limiting device is built into the circuit - a resistor. As a consumer, not a current producer, it effectively copes with the function of separating voltage and input (output) lines. It is used as an addition to active elements of integrated circuits.

There are a lot of types of resistors. Depending on the design, technical parameters and composition, they are:

1. Linear. The resistance remains constant regardless of the potential difference applied to such resistors. They are characterized by a straight volt-ampere line.
2. Non-linear. The resistance depends on the difference between the applied voltage or the passing current. Resistors of this type operate in loose accordance with Ohm's law and have a non-linear characteristic. Used in robotic projects as sensors.
3. Variables. Equipped with a special shaft that allows you to change the resistance parameters during operation.
4. Permanent. The indicators set in them cannot be changed.
5. Carbon. The cores inside such resistors are made of carbon and have cup-shaped contacts. Due to the porous body, they are sensitive to ambient humidity.
6. Foil. They are produced by deposition of sprayed metal on a ceramic base. They are distinguished by high reliability, therefore they are successfully used in basic electronic systems.
7. Wire-wound. Their construction consists of a ceramic core and wire winding made from different metal alloys. The composition of the alloys depends on the required resistance. Shows stable performance at high power.
8. Sintered metal. For their manufacture, a mixture of ceramics and baked metals is used. The percentage of certain components determines the level of resistance.
9. Fusible. In normal operation, they act as limiters. As the power rating increases, they function as fuses, protecting the electrical circuit from short circuits.
10. Heat sensitive. They can give both a positive and a negative coefficient depending on temperature fluctuations.
11. Photosensitive. The main factor affecting their operation is the intensity of the incident light flux. The brighter the light, the lower the resistance of the resistor.

With respect to resistors that change resistance during operation, a term such as tolerance is used, measured as a percentage. It shows how the changing indicators are close to the nominal values. For example, a device with a nominal electrical resistance of 500Ω and a tolerance of 10% can in practice give values ​​in the range from 550 to 450Ω.