What is a Schottky Diode? The Schottky diode or Schottky Barrier Diode unlike the semiconductor diode that has a P-N juntion, has an N-Metal junction. These diodes are characterized by their switching speed and low voltage drop when they are forward biased (typically 0.25 to 0.4 volts). Its symbol is showed on the following diagram. This diode works allmost like the […]

What is a Photodiode? Light Detector Diode.

Photodiode looks similar to the common LED, but it has a feature that makes it very special. It is a device that converts light into electric current.

A phototransistor is essentially the same as a common transistor, but it can work in two different ways:

– As a common transistor, using the base current (IB)
– As a phototransistor, using the light that illuminates this element and that acts as the base current. (IP).

TRIAC. Power control on alternating current (AC)

Triac is a semiconductor device that belongs to the family of thyristor control devices. It is essentially two SCR connected in parallel and backwards, sharing the same gate.

UJT or Unijunction transistor

The UJT or Unijunction transistor is constituted by two polluted regions, with three external terminals: two bases and one emitter.

The SBS – Silicon Bidirectional Switch is a symmetrical low power device used on trigger applications. The SBS is more versatile than the SIDAC.

It also has an additional terminal, which allows you to modify its trigger characteristics with small pulses of current.

JFET Saturation and Breakdown regions The JFET Saturation region In this region the JFET has some linear features that are used in amplification. These features are similar to those of a BJT in the linear region. The JFET behaves as a voltage controlled (VGS) current source which ID is virtually independent of the voltage VDS. The equation that relates the current ID with the […]

JFET Cutoff and Linear regions JFET Cutoff region In this region the current flowing from the Drain to the Source terminals of the JFET is zero (ID = 0). In this case, the voltage between the gate and the source terminals is sufficiently negative to block the flow of the current through the channel between the drain and the source […]

FET characteristics

The N-channel JFET consists of a silicon bar of N-type semiconductor with two P type regions on both sides. JFET is a tri-terminal device whose terminals are called drain, source and gate.

FET

Field effect transistor or FET is a particularly interesting transistor and it can be of two types: the Junction Field Effect Transistor or JFET and the Metal-Oxide Semiconductor Field Effect Transistor (MOSFET).

LDR – Light Dependent Resistor – Photoresistor LDR (light dependent resistor) is a resistor that has a value that varies depending on the amount of light it has on it. Photoresistor is manufactured with crystalline structure materials using its photoconductive properties. The most common crystal used are: cadmium sulphide and cadmium selenide. The photoresistor (LDR) symbol is: LDR’s range values goes from […]

Optocoupler: LED and  phototransistor The Optocoupler is a device that consists of a LED (light-emitting diode) and a phototransistor. When the LED emits light, it illuminates the phototransistor causing a current to flow trought it. These two elements are coupled in the most efficient possible way. The Ic output current of the optocoupler (phototransistor`s collector current) is proportional to the input current IF (LED`s current). The relation […]