{"id":1144,"date":"2026-07-31T16:57:38","date_gmt":"2026-07-31T14:57:38","guid":{"rendered":"https:\/\/www.i8zse.it\/en\/?page_id=1144"},"modified":"2026-07-31T16:57:52","modified_gmt":"2026-07-31T14:57:52","slug":"the-basics","status":"publish","type":"page","link":"https:\/\/www.i8zse.it\/en\/pixie\/the-basics\/","title":{"rendered":"The basics"},"content":{"rendered":"<h1>Basic concepts<\/h1>\n<p>To get started, we need to quickly review some basic concepts that will provide the <em>common ground<\/em> needed to better understand the following steps.<\/p>\n<h2 id=\"corrente-continua\">Direct current<\/h2>\n<p>Direct current is a unidirectional flow of electrons: electrons always move in the same direction, with an intensity that may also vary over time. A battery is the most common example of a direct current source.<\/p>\n<p><a href=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/lampadina.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3734\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/lampadina.png\" alt=\"\" width=\"273\" height=\"137\" \/><\/a><\/p>\n<p>Two quantities describe what happens in a circuit of this type:<\/p>\n<ul>\n<li><span style=\"font-size: 14pt;\">the <strong>difference in electrical potential<\/strong> between the two electrodes (the two terminals of the battery) is called <strong>voltage<\/strong>;<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">the <strong>amount of electrical charge flowing<\/strong> between the two electrodes is called <strong>current<\/strong>.<\/span><\/li>\n<\/ul>\n<p>A comparison that helps fix these concepts is the hydraulic analogy: voltage is similar to the <em>pressure<\/em> of water inside a pipe, while current is similar to the <em>flow rate<\/em>, that is, the amount of water that actually flows.<\/p>\n<h2 id=\"corrente-alternata\">Alternating current<\/h2>\n<p>In alternating current, the flow is not constant in a single direction, but consists of a succession of positive and negative pulses: the current continuously changes direction, following a regular pattern over time.<\/p>\n<p><a href=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/sinusoide.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3735\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/sinusoide.jpg\" alt=\"\" width=\"225\" height=\"139\" \/><\/a><\/p>\n<p>Some key concepts:<\/p>\n<ul>\n<li><span style=\"font-size: 14pt;\">the <strong>voltage<\/strong> of an alternating signal can be expressed in different ways: as peak value (the maximum reached by the waveform) or, more commonly, as RMS value (Root Mean Square), which is the value normally used to indicate the voltage of household electrical networks;<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">the <strong>number of pulses per second<\/strong> is called <strong>frequency<\/strong>, and is measured in Hertz (Hz): later we will see that a few tens of Hertz can make the difference between correctly hearing a CW signal or no longer being able to receive it.<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">the &#8220;standard&#8221; waveform of alternating current follows a curve called a <strong>sine wave<\/strong>.<\/span><\/li>\n<\/ul>\n<h3 id=\"la-sinusoide\">The sine wave<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-3736 size-full\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/sinusoide2.jpg\" alt=\"\" width=\"745\" height=\"208\" \/><\/p>\n<p>The sine wave is the graphical representation of oscillations: it is the shape that would be produced, for example, by the trace left by a pen attached to an oscillating spring, if a sheet of paper were moved underneath it at a constant speed.<\/p>\n<p>It is a relatively simple signal to generate, but very difficult to obtain in a perfectly <em>pure<\/em> form: any real electronic circuit introduces imperfections, to a greater or lesser extent. Any alteration of the waveform compared with a pure sine wave is called <strong>distortion<\/strong>, and distortions almost always have negative effects on signal quality (we will return to this topic later when discussing harmonics).<\/p>\n<h2 id=\"corrente-alternata-e-radio\">Alternating current and radio<\/h2>\n<p>Alternating current and radio are intrinsically connected. The mechanism, in summary, is the following:<\/p>\n<ol>\n<li><span style=\"font-size: 14pt;\">the &#8220;radio&#8221; originates from an alternating current generated by the transmitter;<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">this current is transferred to the <strong>antenna<\/strong>, which acts as a transducer;<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">the antenna converts part of the energy of the electrical current into an <strong>electromagnetic field<\/strong> radiated into space;<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">the electromagnetic field spreads from the antenna and propagates through space, reaching receivers.<\/span><\/li>\n<\/ol>\n<p>Everything we will do while building the Pixie \u2014 generating a stable frequency, mixing it, amplifying it \u2014 ultimately serves the purpose of correctly producing and managing this alternating current.<\/p>\n<h2 id=\"le-unit-di-misura\">Units of measurement<\/h2>\n<p>To describe these phenomena accurately, we need shared units of measurement:<\/p>\n<ul>\n<li><span style=\"font-size: 14pt;\">voltage is measured in <strong>Volts<\/strong> (V);<br \/>\n<\/span><a href=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/tensione.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3737\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/tensione.jpg\" alt=\"\" width=\"233\" height=\"129\" \/><\/a><\/li>\n<li><span style=\"font-size: 14pt;\">the <strong>current<\/strong> flowing in a circuit is related to its <strong>resistance<\/strong>, and is measured in <strong>Amperes<\/strong> (A);<br \/>\n<a href=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/corrente.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3738\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/corrente.jpg\" alt=\"\" width=\"219\" height=\"121\" \/><\/a><\/span><\/li>\n<\/ul>\n<ul>\n<li><span style=\"font-size: 14pt;\">resistance is measured in <strong>ohms<\/strong> (\u03a9);<\/span><\/li>\n<li><span style=\"font-size: 14pt;\">power is measured in <strong>Watts<\/strong> (W), and in direct current it is the product of Volts multiplied by Amperes.<\/span><\/li>\n<\/ul>\n<p><a href=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/misura.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3739\" src=\"https:\/\/www.i8zse.it\/wp-content\/uploads\/2026\/07\/misura.jpg\" alt=\"\" width=\"258\" height=\"194\" \/><\/a><\/p>\n<p>There are formulas that allow us to calculate one of these quantities when the others are known \u2014 the most important one, <strong>Ohm&#8217;s law<\/strong>, will be examined in detail when we discuss resistors.<\/p>\n<h2 id=\"multipli-e-sottomultipli\">Multiples and submultiples<\/h2>\n<p>Many of the units we will use (especially the Farad, the unit of measurement for capacitor capacitance) are, in practical electronics, either too large or too small to be used directly. For this reason, multiples and submultiples of the basic units are used by applying prefixes. It is useful to always keep in mind the relationship between prefixes: in electronics, prefixes normally differ by a factor of one thousand.<\/p>\n<table>\n<thead>\n<tr>\n<th>Prefix<\/th>\n<th>Symbol<\/th>\n<th>Value<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Tera<\/td>\n<td>T<\/td>\n<td>1,000,000,000,000<\/td>\n<\/tr>\n<tr>\n<td>Giga<\/td>\n<td>G<\/td>\n<td>1,000,000,000<\/td>\n<\/tr>\n<tr>\n<td>Mega<\/td>\n<td>M<\/td>\n<td>1,000,000<\/td>\n<\/tr>\n<tr>\n<td>Kilo<\/td>\n<td>k<\/td>\n<td>1,000<\/td>\n<\/tr>\n<tr>\n<td>Milli<\/td>\n<td>m<\/td>\n<td>1\/1,000<\/td>\n<\/tr>\n<tr>\n<td>Micro<\/td>\n<td>\u00b5<\/td>\n<td>1\/1,000,000<\/td>\n<\/tr>\n<tr>\n<td>Nano<\/td>\n<td>n<\/td>\n<td>1\/1,000,000,000<\/td>\n<\/tr>\n<tr>\n<td>Pico<\/td>\n<td>p<\/td>\n<td>1\/1,000,000,000,000<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>These prefixes will appear constantly as we read the values printed on components (especially capacitors), so it is worth learning them well from the beginning (or keeping this table within reach).<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Basic concepts To get started, we need to quickly review some basic concepts that will provide the common ground needed to better understand the following steps. Direct current Direct current is a unidirectional flow of electrons: electrons always move in the same direction, with an intensity that may also vary over time. A battery is [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1145,"parent":1140,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"iawp_total_views":0,"footnotes":""},"class_list":["post-1144","page","type-page","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>The basics - I8ZSE<\/title>\n<meta name=\"description\" content=\"73Pixie Course: Getting familiar with the basics of electronics\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.i8zse.it\/en\/pixie\/the-basics\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The basics - I8ZSE\" \/>\n<meta property=\"og:description\" content=\"73Pixie Course: Getting familiar with the basics of electronics\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.i8zse.it\/en\/pixie\/the-basics\/\" \/>\n<meta property=\"og:site_name\" content=\"I8ZSE\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-31T14:57:52+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.i8zse.it\/en\/wp-content\/uploads\/2026\/07\/misura.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"258\" \/>\n\t<meta property=\"og:image:height\" content=\"194\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"5 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.i8zse.it\\\/en\\\/pixie\\\/the-basics\\\/\",\"url\":\"https:\\\/\\\/www.i8zse.it\\\/en\\\/pixie\\\/the-basics\\\/\",\"name\":\"The basics - 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