Electronics

Construction and Working of Light Emitting Diode A PN junction diode, which emits light when forward biased, is known as a light emitting diode (abbreviated as LED). The emitted light may be visible or invisible. The amount of light output is directly proportional to the forward current. Thus, higher the forward current, higher is the […]

LCD Construction and Working A liquid crystal is a material (usually, an organic compound) which flows like a liquid at room temperature but whose molecular structure has some properties normally associated with solids. As is well-known, the molecules in ordinary liquids have random orientation but in a liquid crystal they are oriented in a definite

Segment Displays A segment display is a form of electronic display device for displaying alphanumeric character decimal numerals that is an alternative to the more complex dot-matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, and other electronic devices for displaying numerical information. In seven segments display, as its name indicates, is

Photodiode It is a two-terminal junction device which is operated by first reverse-biasing the junction and then illuminating it. A reverse-biased P-N junction has a small amount of reverse saturation current Is (or I0) due to thermally-generated electron-hole pairs. In silicon, Is is the range of nano-amperes. The number of these minority carriers depends on

Tunneling Effect In a normally-doped P-N junction, the depletion layer is relatively wide and a potential barrier exists across the junction. The charge carriers on either side of the junction cannot cross over unless they possess sufficient energy to overcome this barrier (0.3 V for Ge and 0.7 V for Si). As is well-known, width

Varactor Diode The varactor diode is a semiconductor, voltage-dependent variable capacitor alternatively known as varicap or voltacap or voltage-variable capacitor (VVC) diode. Basically, it is just a reverse-biased junction diode whose mode of operation depends on its transition capacitance (CT). We know that the reverse-biased junctions behave like capacitors whose capacitance is ∝ 1/VRn where

J.S. Kilby of Texas Instruments was the first person to develop (in 1959) an integrated circuit — a single monolithic silicon chip in which active and passive components were fabricated by successive deposition, etching and diffusions. He was soon followed by Robert Noyce of Fairchild who successfully fabricated a complete IC including the interconnections on

IC Voltage Regulator Circuits Due to low-cost fabrication technique, many commercial integrated-circuit (IC) regulators are available since the past two decades. These include fairly simple, fixed-voltage types of high-quality precision regulators. These IC regulators have much improved performance as compared to those made from discrete components. They have a number of unique build-in features such

JFET Construction and Working The junction field-effect transistor (JFET) is a three element electronic device. Its operation is based on the conduction of current carriers through a single piece of semiconductor material. This piece of material is called the channel. An additional piece of semiconductor material is diffused into the channel. This element is called

Light Sensitive Devices Light-sensitive devices include photo cells, solar cells, photo-diodes, and photo-transistors.  Photo Cell It is a light-sensitive device in which the internal resistance changes with a change in light intensity. The resistance change is not proportional to the light striking it. The photo cell is made from light-sensitive material such as cadmium sulfide