In a digital circuit, power supply voltage levels are constrained to two distinct values – “logic high voltage” (called LHV or Vdd) and “logic low voltage” (called LLV or GND). The GND node in any circuit is the universal reference voltage against which all other voltages are measured (in modern digital circuits, GND is typically the lowest voltage in the circuit). In a schematic, it is often difficult to show lines connecting all GND nodes; rather, any nodes labeled GND are assumed to be connected into the same node. Often, a downward pointing triangle symbol, is attached to a GND node in addition to (or instead of) the GND label. The Vdd node in a digital circuit is typically the highest voltage, and all nodes labeled Vdd are tied together into the same node. Vdd may be thought of as the “source” of positive charges in a circuit, and GND may be thought of as the “source” of negative charges in a circuit. In modern digital systems, Vdd and GND are separated by anywhere from 1 to 5 volts. Older or inexpensive circuits typically use 5 volts, while newer circuits use 1-3 volts.
Electronic components are often assembled and interconnected on a flat surface known as a circuit board. The several types of existing circuit boards may be divided into two broad categories: those intended for prototype or experimental circuits; and those intended for production and/or commercial sale. Circuit boards used for experimental work are often referred to as breadboards or protoboards. Breadboards allow engineers to construct circuits quickly, so that they can be studied and modified until an optimal design is discovered. In a typical breadboard use, components and wires are added to a circuit in an ad hoc manner as the design proceeds, with new data and new understanding dictating the course of the design. Since breadboard circuits exist only in the laboratory, no special consideration need be given to creating reliable or simple-to-manufacture circuits – the designer can focus exclusively on the circuits behavior. In contrast, circuit boards intended for production or commercial sale must have highly reliable wires and interconnects, permanent bonds to all components, and topographies amenable to mass production and thorough testing. And further, they must be made of a material that is reliable, low-cost, and easy to manufacture. A fiberglass substratewith copper wires (etched from laminated copper sheets) has been the PCB material of choice for the past several decades. The Digilent board is a simple example of such a board. Note that most often, production circuit board designs are finalized only after extensive breadboard phases. Components are permanently affixed to production boards using the soldering process.
Hit For More Images Gallery
Altrushare - Wiring Diagram Gallery
Copyright © 2003 - 2018 Domain Media. All sponsored products, company names, brand names, trademarks and logos arethe property of their respective owners.