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
The bipolar junction transistor is a current-controlled device, while the field-effect transistor (FET) is a voltage-controlled device. The field-effect transistor uses basically no input current. Instead, output current flow is controlled by a varying electric field, which is created through the application of a voltage. This is the origin of the term field effect. The
Operational amplifiers (op-amps) are analog circuit components that require power to operate. They are widely used in amplification and signal-conditioning circuits. The symbol for an op-amp is shown in Figure 1. The symbol is a triangle, with two leads drawn on one side of the triangle, and the third lead is drawn at the apex
The 555 timer chip (such as the NE555 8-pin chip from Texas Instruments) is an integrated circuit that uses a transistor, resistors, flip-flops, comparators, and capacitors to produce a variety of clock signals, including a fixed pulse, a periodic signal, and a frequency dividing signal. The NE555 can operate over a wide voltage supply range
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Figure 1(a) shows a boost converter, another basic topology for converters. A boost converter always steps the voltage up. The theory of operation is similar to that for a buck converter in some ways but very different in others. Boost Converter Working For instance, when the pulse is high, the switch is closed and energy
Figure 1(a) shows a buck converter, the most basic topology for converters. A buck converter always steps the voltage down. A transistor, either a bipolar junction or a power FET, is used as the switching device. A rectangular signal out of the pulse-width modulator closes and opens the switch. A comparator controls the duty cycle
This article covers the following items about electrical timers: The five sections of timers Nine timer operating principles Five common modes of timer operations Timer charts Sections of Electrical Timer Figure 1 provides a block diagram that shows the five functional sections of a timer. Timers can be divided into the following sections: Power or