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 […]

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.

The Field Effect Transistor (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 – The Metal-Oxide Semiconductor Field Effect Transistor (MOSFET). These devices have a high input impedance (1012 ohms) and they are controlled by voltage. Both devices are used as an amplifier or a […]

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. The photoresistor (LDR) symbol is: Photoresistor is manufactured with crystalline structure materials using its photoconductive properties. The most common crystal used are: cadmium sulphide and cadmium selenide. 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 […]

Seven Segments Display, 7-segment Display The 7-segment display, is a component that is used to represent numbers in many electronic devices. Today, it is very common to find LCDs in many electronic equipments (due to its very low energy demand), but there are many that still use the 7-segment display for its simplicity. This element is made in a […]

LED – Light-emitting diode Light-emitting diode (LED) is a special type of diode, that emits light when it is forward biased. There are LEDs of various colors. LED colors depend on the material with which they were built. There are red, green, yellow, amber, infrared, etc. If a current flows through a semiconductor diode, there are electrons and holes […]

The 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 current. Incident Light (red  arrows). Direction of the generated current (blue arrow). This current flows on the opposite direction of the arrow of the diode and […]