Semiconductor

OSI NETWORK PROTOCOLS MODEL

Neither the OSI model and its protocols nor the TCP/IP model and its protocols are perfect. Quite a bit of criticism can be, and has been, directed at both of them. In this section and the next one, we will look at some of these criticisms. We will begin with OSI and examine TCP/IP afterward.At [...]

{ 0 comments }

Light Activated SCR

Like bipolar transistors, SCRs and TRIACs are also manufactured as light-sensitive devices, the action of impinging light replacing the function of triggering voltage. Optically-controlled SCRs are often known by the acronym LASCR, or Light Activated SCR. Its symbol, not surprisingly, looks like this: Optically-controlled TRIACs don’t receive the honor of having their own acronym, but [...]

{ 1 comment }

DIAC

Like all diodes, Shockley diodes are unidirectional devices; that is, they only conduct current in one direction. If bidirectional (AC) operation is desired, two Shockley diodes may be joined in parallel facing different directions to form a new kind of thyristor, the DIAC: A DIAC operated with a DC voltage across it behaves exactly the [...]

{ 0 comments }

Hysteresis

Thyristors are a class of semiconductor components exhibiting hysteresis, that property whereby a system fails to return to its original state after some cause of state change has been removed. A very simple example of hysteresis is the mechanical action of a toggle switch,when the lever is pushed, it flips to one of two extreme [...]

{ 0 comments }

Junction Field Effect Transistor

A transistor is a linear semiconductor device that controls current with the application of a lower-power electrical signal. Transistors may be roughly grouped into two major divisions: bipolar and field-effect. In the last chapter we studied bipolar transistors, which utilize a small current to control a large current. In this chapter, we’ll introduce the general [...]

{ 0 comments }

Common Base Amplifier

Common Base Amplifier: The final transistor amplifier configuration we need to study is the common-base. This configuration is more complex than the other two, and is less common due to its strange operating characteristics. It is called the common base configuration because (DC power source aside), the signal source and the load share the base [...]

{ 0 comments }

Meter Check of a Transistor

Meter Check of a Transistor: Bipolar transistors are constructed of a three-layer semiconductor “sandwich,” either PNP or NPN. As such, they register as two diodes connected back-to-back when tested with a multimeter’s “resistance” or “diode check” functions: Look at the picture of diode check functions: Here assuming the use of a multimeter with only a [...]

{ 0 comments }

Transistor Saturation

The term saturation is applied to any system where levels have reached their maximum values. A saturated sponge is one that cannot hold another drop of liquid. For a transistor operating in the saturation region, the current is a maximum value for the particular design. Change the design and the corresponding saturation level may rise [...]

{ 0 comments }

Organic Light Emitting Diodes

The increasing use of digital displays in calculators, watches, and all forms of instrumentation has contributed to the current extensive interest in structures that will emit light when properly biased. The two types in common use today to perform this function are the light-emitting diode (LED) and the liquid crystal display (LCD). Since the LED [...]

{ 0 comments }

← Previous Entries