One of the main characteristics is the power dissipation. The power dissipation is the power that a resistor can dissipate without being damaged. It is measured in watts. It is calculated by the formula power=current2 * resistance, or P = I2R

Every substance has its own resistance, some are very large (wood, plastic), others are small (metals, liquids). The resistance depends on the material (gold has less resistance than aluminum), on the length of the conductor (direct correlation: the longer the greater the resistance) and on the area of the cut of the conductor (the greater the area, the less resistance).

Now let’s talk about the use of permanent resistors in circuits.
If you did not find a resistor with the right resistance when assembling the circuit, you can put two or more resistors in series (their total resistance will be the right resistance). You can put them in parallel and find their resistance by the formula 1/Robsh = 1/R1 + 1/R2 + 1/R3.

Basically we will use carbon resistors. If you break it down (for the sake of interest, of course), you will see a layer of ceramic covered with a thin carbon film.

Most resistors are labeled with color bars (usually four, less often five), or a numerical designation. For example, 1R means that the resistor has a resistance of 1 ohm, 1.5K means 1.5 kilohms (1500 ohms). You can find the resistance by color banding using an online service: resistor color-coding calculator.

There are also variable resistors that have the ability to change their resistance. They are used to change current, voltage, etc. (for example: change the volume and tone). Most often on a circuit diagram are shown as follows:
Variable resistor designation

About their types below.

Variable resistors are:
1) Single and twin
2) Single and multi-turn
3) With or without switch

By nature of resistance change:
1) Linear i.e. In proportion to the angle of rotation of the axis (group A)
2) Inversely logarithmic, i.e. gradually increasing at first, and then sharply increasing (group B)
3) Logarithmic (group C)
4) And others (groups E, I).

There are wire-wound and non-wire-wound (film) variable resistors. Wire-wound resistors are characterized by high stability, a relatively low level of their noise and low TCR.

The post What is a resistor? appeared first on DX-Arnode.

A capacitor is a device that is used to store electricity because of the dielectric (non-conductive material) used in it. On wiring diagrams, it is marked with a symbol resembling two large letters T placed on its side and facing each other with their tops. From a practical point of view, if a device fails due to a damaged capacitor, the most important question is how to check whether the capacitor is in working order. If its visual inspection does not answer this question, you should measure the two most important parameters that define each capacitor: capacitance and series resistance.

What kind of household appliances have capacitors?

Although the principle of capacitors is always the same, they use different dielectrics (insulators). Therefore, in terms of design, capacitors are divided into ceramic, foil and electrolytic. In household appliances, the latter are the most common, and can be found in every device with a motor and electronics.

Why are capacitors used in household appliances?

Capacitors in household appliances have two functions: starting and protection against interference. Their use in the starting function is related to proper motor starting, and the interference suppression effect ensures the electromagnetic compatibility of electrical devices. What it means. Most electrical and electronic devices emit interference, among other things the correct parameters of the electrical network.

How do I check a capacitor?

How do I check the inrush and interference suppression capacitor at home? Can it be done without using specialized equipment? Why is it important to detect such a defect at all?

The only capacitor whose efficiency can be evaluated in some cases without the use of any devices is an electrolytic capacitor. Unfortunately, the absence of damage to other types of capacitors as well as electrolytic defects in most cases can only be evaluated by measuring capacitance and series resistance.

How to check an electrolytic capacitor?

In some cases, a damaged electrolytic capacitor makes it much easier to identify its failure because of the use of electrolyte as an insulator. This type of capacitor behaves like an old battery, that is, it “bulges” and you can visually detect electrolyte leakage in it. Such a capacitor with a bulging bottom and contaminated by leaking chemicals should of course be replaced immediately. However, if the capacitor looks visually good, all that remains is measurement.

The post How to check a capacitor appeared first on DX-Arnode.

I have picked up some programs for tracing a printed circuit board.

Sprint-Layout
The most popular program among hams, almost all beginners started with it. It has a simple and intuitive interface, and there is a russified version. Sprint-Layout has a large database of electronic components (macros), which can be downloaded from the Internet. A huge number of training videos on YouTube, will help you learn the whole interface and learn to draw printed circuit boards. The program is conditionally – free.

Chinese online service with great opportunities. In China students create projects with this service and it is taught in some educational institutions. The main convenience lies in the fact that created projects can be edited on any computer with Internet access, it is only necessary to pass a simple registration to create an account. Easyeda has a huge base of electronic components that are constantly updated and added by users. This service has a function of automatic tracing circuit boards and simulation of electronic circuits. The interface is intuitive. After the printed circuit board is laid out on the tracks it can be ordered in this service, and industrial quality, or you can not order, and print out on a printer and do it yourself. You can also share the project with other users or create the project together.

ZenitPCB
Easy and free program to draw schematic diagrams and trace it. The disadvantage is the limitation of 800 pads. The base of elements is about 1000.

DesignSpark PCB
Powerful program with automatic PCB trace. Suitable for beginners and professionals alike.
DesignSpark PCB is a free program with built-in specialized calculators for various calculations to make the selection of components easier. On the official site you can download a library of ready-made printed circuit boards.

I use two;
Sprint-Layout program
Online service easyeda.com.
For my work, at this stage of my development, this is enough. In mastering these programs, any beginner radio amateur can cope.

The post Programs for PCB layout appeared first on DX-Arnode.