ElectoWorld

Schottky diodes,metal/semiconductor junction: this heterogeneous junction is characterized  by the absence of storage of charges, it is therefore very fast. It is widely used in circuits fast logic (TTL Schottky). Schottky diode symbol A schottky diode works exactly the same as a diode.The differences are: At the threshold voltage, which is no longer 0.7V, but 0.3V, at 0.4V In terms of speed, schottky diodes are much faster and more expensive Application: Logic circuits: TTL LS technology and derivatives Switching power supply POWER SCHOTTKY DIODES: reduction of the voltage drop in the on state (0.4V at 1A/mm²). no reverse recovery phenomenon (therefore very fast diode)  but appearance of a negative current of the same order of magnitude as the current of the fastest diodes. only limitation: Reverse voltage withstand. it is difficult to exceed 200V Varactor diode This reverse biased diode behaves like a very low value capacitor, the capacity of which...

A photodiode is a semiconductor component that detects radiation from the optical domain and transforms it into an electrical signal. Working principle When a semiconductor is exposed to a luminous flux, the photons are absorbed provided that the energy of the photon E (ph) is greater than the width of the forbidden band Eg.  This corresponds to the necessary energy that the electron must absorb so that it can leave the valence band (where it serves to ensure the cohesion of the structure) towards the conduction band, thus making it mobile and able to generate a Electric power. The existence of the forbidden band implies the existence of an absorption threshold such  that  E(ph)=Eg. During the absorption of a photon, two phenomena can occur: Photoemission: this is the exit of the electron from the photosensitive material. The electron can only exit if it is excited near the surface. Photoconductivity: the electron is released inside the material. The electrons th...

The 78XX voltage regulator The 78XX voltage regulator is one of the most common components on electronic boards. There are several models depending on the voltage or current you want at the output. This is called a linear regulator the last two digits give you the output voltage eg 7805 is a 5Vdc regulator, 7812 a 12Vdc regulator, their input voltage can go up to 35Vdc. A regulator is a 3-terminal component used to regulate voltage in an electrical circuit. Regulators are very useful in electrical circuits when you need a stable voltage. Indeed a regulator makes it possible to enter the output voltage very fixed, which is preferable for components such as microcontrollers. 7805 voltage regulator For example for a + 5V regulator, you will have a maximum drop to + 4.97V for high currents. Which is much more precise than batteries or a power adapter.     Above here is the usual circuit, the capacitors serving as an interference suppressor. The minimum input volt...

  The LM35 temperature sensor is an analog temperature sensor .This integrated circuit has 3 pins and generates an output voltage in linear relation with the temperature expressed in degrees Celsius The LM35 sensor is able to measure temperatures ranging from (-55 ° C to + 150 ° C) in its most precise version and with the right mounting, enough to measure any temperature. The analog output of the sensor is proportional to the temperature. It suffices to measure the voltage at the output of the sensor to deduce the temperature. Each degree Celsius corresponds to a voltage of + 10mV. The LM35 does not require any external calibration or size and maintains an accuracy of (+ / -0.4 ° C) at room temperature and (+ / - 0.8 ° C) over a range of 0-100° C. The temperature measured by the sensor is given by the relation: T = Vout / 10 with: T: Temperature [° C] Vout: Output voltage [mV]   DHT22 sensor The DHT22  temperature and humidity sensor communicates with ...

  A triac is made up of 2 thyristors placed head-to-tail in order to be bidirectional, usable in AC.It is also called solid state relay and it is the basis of dimmers. Is an active component increasingly used in today's assemblies. Its direct use on the sector makes it possible to switch large loads from much more modest circuits. Triac Symbol The three electrodes of the triac are called gate (control electrode), and MT1 and MT2 (for Anodes 1 and 2). These last two electrodes ensure the main conduction. Operation Once triggered by an impulse on the gate, the triac lets the current flow until this current falls below a critical threshold (holding current). Due to this structure, the triac is used to control the passage of the two halfwaves of an alternating current (while the thyristor only conducts during one halfwave). The circuit above is very simple trigger. The phase shifter network Rc charges the capacitor. when it reaches a voltage at the terminals, greater than the...