What is Zener diode ? what do you know about Zener Diode and its Working function ?

<div dir="ltr" style="text-align: left;" trbidi="on"> <br /> <h2 style="text-align: left;"> <i style="mso-bidi-font-style: normal;">                            <u>Zener Diode</u></i></h2> <div class="MsoNormal"> <i>                         A properly doped crystals diode which has a sharp breakdown voltage is known as Zener diode.<o:p></o:p></i></div> <div class="MsoNormal"> <i>The circuit symbol and characteristics curve of a zener Diode is shown below,</i><o:p></o:p></div> <br /> <table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody> <tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNI5WLwKQX13MmJDHWMhVSBMWk0UmJiU0JCm6_n3dj4Z9-hQAXuNO3OlLo4opclkhN6xAbB7xAFyTlCIB8GZN3pUFx_pXPBJwNh9PhIGsmgm5beeC-a5SIEGCOdFtDwLhvQII0FCZRQOWs/s1600/Zener-Diode-and-Its-Symbol.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="223" data-original-width="603" height="147" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNI5WLwKQX13MmJDHWMhVSBMWk0UmJiU0JCm6_n3dj4Z9-hQAXuNO3OlLo4opclkhN6xAbB7xAFyTlCIB8GZN3pUFx_pXPBJwNh9PhIGsmgm5beeC-a5SIEGCOdFtDwLhvQII0FCZRQOWs/s400/Zener-Diode-and-Its-Symbol.jpg" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Circuit symbol (Image taken from google image)</td></tr> </tbody></table> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> <br /></div>                         <i>The forward characteristics of a zener is similar to that of an ordinary diode.The reverse characteristics exhibits a region in which the voltage across the diode is almost independent of diode current. This fact makes </i><br /> <div> <i>Zener Diode useful as a voltage </i></div> <div> <i>regulator </i><i>device.</i><br /> <div> <br /> <br /> <table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody> <tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigOmZ86va4KiYVUtCEh6cOUH6F7-Z8fvuuM2rofSRgeOZ2qDDFq1SkuycEn9OPrBOltqGNVdq0TfRcw4Bp8u_qxqAE6ob7gPnryGtJ_XWSvyXOkUe12pduzuXuu9tEIMLXHbJeU6W5Wi2Z/s1600/image_130.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="396" data-original-width="608" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigOmZ86va4KiYVUtCEh6cOUH6F7-Z8fvuuM2rofSRgeOZ2qDDFq1SkuycEn9OPrBOltqGNVdq0TfRcw4Bp8u_qxqAE6ob7gPnryGtJ_XWSvyXOkUe12pduzuXuu9tEIMLXHbJeU6W5Wi2Z/s320/image_130.png" width="320" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Characteristics curve of zener diode (image taken from google image)</td></tr> </tbody></table> <ul style="text-align: left;"> <li><i>Manufacturers generally specify Zener diodes according to their Zener voltage (Vz) and maximum allowable power dissipation Pz.                                                                                                       If Vz is the voltage of the Zener Diode then maximum rated current,                                                          </i><div class="MsoNormal">                           Iz_{max = (Pz/Vz)                                                                                                                                        <i> <span style="font-size: small;"> If current through Zener exceeds Izm, it will be destroyed.</span></i>}</div> <div class="MsoNormal"> <!--[endif]--><i><o:p></o:p></i></div> </li> <li>_{<i><span style="font-size: small;">Another parameter of interest is knee current which correspond to the knee of reverse characteristics curve. Below the knee current </span></i>} Iz_{min <span style="font-size: small;">, <i>Zener fail to regulate output voltage.</i></span>}</li> </ul> <h3 style="text-align: left;"> <i>         Zener Diode as a Voltage Regulator</i></h3> <div> <i>                            In a voltage regulated power supply, the output voltage is constant and its independent of variation of input supply voltage and load current. The circuit diagram of a Zener diode voltage regulator is shown below.</i></div> <div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhG0vNmcCSRUdSk993vKLPHB5BQwz0irHvkeu0jFOsWPgrLPRyqxDSvOaTNDDaJwbYNv963i-7PJ03Ta-bKZj_4MAQPPVQ-BcRnLh5qlm9EtXFiCrZ2dh97Ei33Nrh8ccOp6RxrbUvsdxPL/s1600/IMG_20180927_120806_HDR.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="973" data-original-width="1600" height="242" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhG0vNmcCSRUdSk993vKLPHB5BQwz0irHvkeu0jFOsWPgrLPRyqxDSvOaTNDDaJwbYNv963i-7PJ03Ta-bKZj_4MAQPPVQ-BcRnLh5qlm9EtXFiCrZ2dh97Ei33Nrh8ccOp6RxrbUvsdxPL/s400/IMG_20180927_120806_HDR.jpg" width="400" /></a></div> <i><br /></i></div> <div> <i><br /></i></div> <div> <i><br /></i></div> <h4 style="text-align: left;"> <i>Principle of Working</i></h4> <div> <i>In the breakdown region, the output across the zener diode is almost independent of current through it. Hence zener diode maintain a constant output voltage </i>V₀≈ V_{z <span style="font-size: small;">, <i>independent of variation of load current (Load regulation) or variation of input voltage   </i></span>}<i>V_{i   (<span style="font-size: small;">Line Regulation</span>) <span style="font-size: small;">as along as the diode is at break down region.</span>}</i></div> <div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiD85O3f96Ey98eRVevvuI-6g6CAPw1cAYhEJ-eZlLnG6pJBjVi5fvCjVZiqyMv-UpeKUWkc1agJiMf3PY2yiwQI8WTQlbHGxpmVvbtq3X53bqVAOwxO7hYtiGVrDuFUDxHk8AnIjqQuZsm/s1600/IMG_20180927_120923_HDR.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="337" data-original-width="1600" height="132" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiD85O3f96Ey98eRVevvuI-6g6CAPw1cAYhEJ-eZlLnG6pJBjVi5fvCjVZiqyMv-UpeKUWkc1agJiMf3PY2yiwQI8WTQlbHGxpmVvbtq3X53bqVAOwxO7hYtiGVrDuFUDxHk8AnIjqQuZsm/s640/IMG_20180927_120923_HDR.jpg" width="640" /></a></div> <h4 style="text-align: left;"> <i>_{<span style="font-size: small;">Variation of Output Voltage with Load current</span>}</i></h4> </div> <div style="text-align: left;"> <i>_{<span style="font-size: small;">                        To discuss this we take Vi remains constant and </span>}</i>I_L_{<span style="font-size: small;"><i> to vary, Since </i></span>}V₀≈ V_{z <span style="font-size: small;">, across Zener is fixed; it is independent of </span>}<i> </i>I_L</div> <div class="MsoNormal"> _<o:p></o:p></div> <div style="text-align: left;"> _{<span style="font-size: small;"><i> . </i></span>}<br /> <div class="separator" style="clear: both; text-align: center;"> <span style="font-size: small;"><i><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCM51ab86_FoIv-3wkpS_dWKgRy1nSpfGPFjBRJOOLoKzKWjQ_M9vaK2N5LEpk6N6pO9KKHI-B3ka91CAAaNBykKSeicooP7lGtrvwwrtBxZlCvOsUsWDwawFbngBMefd3KCAacIpNcxFO/s1600/IMG_20180927_120904_HDR.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="338" data-original-width="1600" height="134" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCM51ab86_FoIv-3wkpS_dWKgRy1nSpfGPFjBRJOOLoKzKWjQ_M9vaK2N5LEpk6N6pO9KKHI-B3ka91CAAaNBykKSeicooP7lGtrvwwrtBxZlCvOsUsWDwawFbngBMefd3KCAacIpNcxFO/s640/IMG_20180927_120904_HDR.jpg" width="640" /></a></i></span></div> </div> <div style="text-align: left;"> _{<span style="font-size: small;"><i>                         Thus if load current (</i></span>}I_{L) <span style="font-size: small;"><i>increases, when the supply voltage is fixed, the Zener current </i></span>}<i>_{<span style="font-size: small;"> </span>}</i> Iz <i>decreases by the same amount ; but V₀≈ V_{z   <span style="font-size: small;">remain constant.</span>}</i></div> <h4 style="text-align: left;"> <i>_{<span style="font-size: small;">Variation of Output Voltage with Input Voltage</span>}</i></h4> <div> <i>_{<span style="font-size: small;">                             We take now </span>}</i>_{<span style="font-size: small;"><i> </i></span>}I_{L <span style="font-size: small;"><i>,</i></span>}R_{L <span style="font-size: small;"><i>remains constant and </i></span>}<i>V_{i   <span style="font-size: small;">varying. Since </span>}</i>V_{0 <span style="font-size: small;"><i> tends to remain constant at Vz, </i></span>}<i> </i>I_{L <span style="font-size: small;"><i>remains constant.</i></span>}</div> <div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFjdDovkS0r6VYPKOCYXc0hwb1OFThSGHi9D5adFX2sK_RJBlWVhZlLl5-4i_xsV8gr5KLMC9b3_pDvrmoLfgCUGPZm0IuW7f2a6yJ4Nw4MglQmqVsCR6cH0FpMwJ5cKHTlri67WJL8wRN/s1600/IMG_20180927_120938_HDR.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="929" data-original-width="1600" height="232" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFjdDovkS0r6VYPKOCYXc0hwb1OFThSGHi9D5adFX2sK_RJBlWVhZlLl5-4i_xsV8gr5KLMC9b3_pDvrmoLfgCUGPZm0IuW7f2a6yJ4Nw4MglQmqVsCR6cH0FpMwJ5cKHTlri67WJL8wRN/s400/IMG_20180927_120938_HDR.jpg" width="400" /></a></div> _{<span style="font-size: small;"><i>i.e. In this case Zener current and total current change such ways as to maintain </i></span>}<i> </i>I_{L <span style="font-size: small;"><i>constant and hence to constant i.e. </i></span>}V_{0 <span style="font-size: small;">=</span>}I_LR_{L <span style="font-size: small;">. <i>to be constant.</i></span>}</div> <h4 style="text-align: left;"> <i>_{<span style="font-size: small;"><br /></span>}</i></h4> <div class="MsoNormal"> _<o:p></o:p></div> </div> </div> </div>

What is Zener diode ? what do you know about Zener Diode and its Working function ?

                            Zener Diode                          A properly doped crystals diode which has a sharp breakdown voltage is...

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