Dmitriy Bliznyuk

Saved 3/3/17 2:09 AM from on a note

STABILITRON. Principle of action. Marking  See details »

Video subtitles:
  • 00:00: Hello more zener diodes called reference diodes mostly they intended for stabilization output voltage at fluctuations input voltage for example if load you need get 5 volts and source voltage power fluctuates in within 9 volts to reduce and stabilize the voltage supply this is a power source to the required 5 volts apply zener diode of course can be applied and stabilizers stresses in this case will fit vm 7805 or 7805 however
  • 00:31: application of them is not always justified therefore in separate cases use zener diodes, outside zener- like on diodes and has the next view are manufactured zener diodes plastic body like this one zener diode or in glass body as such zener diode or such a zener diode also manufactured zener diodes in smd buildings like here such a zener diode in glass case or this
  • 01:01: zener diode plastic body with three conclusions packed smd zener now in such tapes to begin zhak zener diodes is denoted by in the following way just like an idiot only not yet dash from the side cathode this conclusion is called the cathode
  • 01:32: and the other is the anode terminal now let's will understand how way zener diode fulfills stabilization voltage to start we need little theory and then we all check for real example main characteristic zener diode however, like a diode is an volt-ampere characteristic or abbreviated Islands it shows dependence of magnitude current flowing through a zener diode of
  • 02:02: attached to it voltage volt-ampere the characteristic has two branches direct after all and back I after all straight after all in shows what values ​​will be flow current through zener diode if to attach a direct voltage however, this fact direct for
  • 02:32: zener diode in practically not used it is a working for conventional diodes normal mode work of a zener diode is the reverse tension therefore, for zener diodes is a working the reverse because located practically parallel to the axis reverse current to This curve is not two characteristic points . 1 and . 2 between these points there is a working region on
  • 03:02: zener at some amount reverse voltage comes electrical breakdown pn junction zener diode and through he begins leak significant current is we denote the stress у с т voltage stabilization first point corresponds minimum current flowing through zener diode second point corresponds to the maximum current flowing through zener diode now look at the curve here is has the form of a line with current through zener from
  • 03:33: minimum values ​​up to the maximum stresses on zener diode practically not changes due to this property and carried out stabilization voltage if current flowing through zener diode will exceed maximum meaning then there will be overheating its structure there will be a thermal breakdown and zener diode will fail now let's consider the scheme and stabilization principle stresses to power source zener diode connects through current-limiting
  • 04:04: resistor r ogre which serves for current limitation flowing through zener diode together with form a divisor voltage note attention in contrast to diode zener diode connects to reverse direction that is, the cathode a plus power supply it anode minus parallel to conclusions zener diode connects load rn on the clamp which is required support stable tension process
  • 04:34: stabilization stresses is next when increase source voltage nutrition increase the total current in the circuit and a hence the current stabilization and st flowing through zener diode vd1 increases voltage drop on current-limiting a resistor in this case stress on zener diode and respectively on load from practically remains unchanged with change resistance loads occur redistribution total current load and current
  • 05:05: zener diode and the voltage at zener diode and load remains practically unchanged if stress on load more stresses stabilization zener diode, you can apply several consistently included zener diodes for example if need to get 10 volts on load stable tension then for lack of necessary zener diode can be turn on sequentially 2 a zener diode of 5 volts also zener diodes successfully used in
  • 05:35: automation systems the quality of sensors voltage for example if the input the voltage will exceed certain tension that is voltage at which will happen breakdown of a zener diode then through a zener diode will begin to leak significant current and this is the current, the relay coil result of a relay will work and give team to others devices or simply signals on excess some level voltage and so now let's all look at a real example source terminals supply
  • 06:05: plus and minus source voltage power under one first seven whole eight tenths of a volt our scheme is pretty just a zener diode and sequentially with him only included limiting the resistor is measured input voltage and see seven and nine almost eight volts now we measure stress on stably we see four whole and almost eight tenths of a volt nominal voltage stabilize this zener diode 4,7 volts that is practically corresponds to it nominal
  • 06:35: value now we increase the voltage input zener diode and current-limiting the resistor we increase almost twice or even twice now we measure the input voltage watch almost 17 volts and the voltage at Zener 4 whole eighty five hundredth of a volt as we see the input voltage has changed in almost two times and the voltage at zener diode changed somewhere on one-tenth of a volt and then it is less now
  • 07:05: let's connect 2 zener diode consistently To obtain Voltage 9 and 4 Volts voltage stabilize each a zener diopter of 4.7 volts but our one zener diode 2 zener diode and only limiting resistor check input voltage almost 17 volts output voltage 2 zener diodes nine as much as 65 hundredths of a volt that is practically equal to the nominal tension stabilization 2 zener diode simple way
  • 07:36: carried out stabilization permanent stresses but apart from stabilization permanent with zener diodes can stabilize and variable the tension for this use consistently counter- switching two zener diodes only at the output we we get not an ideal sinusoidal but with cut tops that is form voltage will be close to the trapezium let's assemble this scheme and so we put together scheme for
  • 08:06: stabilization alternating voltage to two extreme output voltage is applied transformer almost 10 volts and output voltage stabilitronov five as many as four tenths volta draw attention two zener diode included meetings on among themselves in one half-cycle one zener diode works just like a diode second as zener diode in the reverse pavel period another zener diode works as a diode and the former zener diode works as a zener diode now let's
  • 08:36: see the form input voltage schemes of stabilization and at the exit zener form input voltage stabilization schemes we we see a sinusoidal but the current voltage 9 whole four tenths of a volt now we'll see output voltage zener diode like us see the form output voltage zener diode has almost form trapezoid that is, zener diodes just cut tip of a sinusoid the magnitude of which is higher 5 volt active The voltage we see
  • 09:07: exactly 5 volts frequency 50 hertz marking zener diodes apply several ways of marking zener diodes zener diodes and glass case having flexible conclusions are marked by in an understandable way how enclosure rule figures divided the Latin letter b for example 48 denote that stress stabilization 4.7 Volt 9 in 1 means 9,1 volts and so on
  • 09:37: zener diodes plastic housing is marked in the form of numbers and letters by themselves these figures they do not talk about anything but with they can be datasheeted easy to decipher for example designation 1 m 53 49b means that voltage stabilization of 12 volts except the voltage such marking takes into account other options zener diode black or a gray ring casing zener diode denotes its cathode
  • 10:07: smd marking zener diodes in quality of marking smd zener diode applies colored rings similar marking It is also used for Soviet not zzz zener diodes in import zener diode colored rings are applied by cathode for decoding color rings easier use datasheets or online decryptor for lack of datasheet and similar decoder of voltage stabilization can defined by experienced first by using a multimeter
  • 10:37: need to identify relevant conclusions and connect zener diode through current-limiting resistor then apply voltage from regulated power source smoothly changing and the voltage needed follow the change stresses on Zener diode if with change in source voltage supply voltage at zener diode does not changed then this and will its voltage stabilization there is smd a zener diode with three conclusions one of them is not these conclusions can be identify with
  • 11:07: using a multimeter Zener diode conclusions exactly the same is defined as conclusions of the diode multimeter is established continuity mode and touch probes conclusions we do not believe in one position zener diode current and in the other does not conduct I repeat once more ring applied to zener diode housing denotes its cathode power dissipation zener diodes for action flowing through Zener current he heats up allocated heat dissipates into the surrounding
  • 11:37: space than more zener diode can russia heat not changing clothes higher power scattering and more current can be pass through as a rule than more dimensions zener themes more from him power dissipation power dissipation the largest a zener diode of 5 watts secondary zener diode 1 and 3 watt and the smallest half a watt on it all thanks for attention and before new meetings