【精品】电子技术专业 毕业论文文献翻译 中英文对照.doc
Information on power supplies
There are many types of electrical and electronic power supplies, providing various alternating current (AC) and direct current (DC) voltages for equipment operation. DC voltages are needed for most electronic circuits, and generally an electronic power supply is considered as a device that converts AC into DC. The AC voltage from the power lines can be rectified directly or passed through an isolation transformer (a turn’s ratio of 1:1). Depending on the value of DC voltage needed, the transformer may be of either a step-up or step-down type. After the transformer, the AC is rectified into pulsating DC by diodes in the form of a half-wave rectifier, a full-wave rectifier, or a bridge (full-wave) rectifier. The pulsating DC is then filtered or smoothed out by capacitors, inductors, and resistors so as to produce a constant DC output.
In this unit the following topics are covered: basic concepts about Logic circuits, number representations, combinatorial logic circuits, sequential logic circuits, introduction to CMOS digital circuits,Logic operations theorems and Boolean algebra, Number operations (binary, hex and integers), combinatorial logic analysis and synthesis, sequential logic analysis and synthesis, registers, counters, bus systems, CAD tools for logic design.
The number system with which we are most familiar is the base 10, or decimal system. Recent technological developments have created the need for other number systems. The puter, for example, required the development of systems that were easily adapted to electronic processes.
These number systems were the binary (base 2), octal (base 8), and hexadecimal (base 16). The binary system is the primary language of puter and the octal and hexadecimal systems are usually used munication with puter and for storage of information within puter
puters can only process binary numbers or numbers coded in other systems such as octal and hexadecimal, the decimal system must be converted to one of these other systems before it can be processed by puter.
When puter finishes its operations on the information, the output is printed or displayed in number system other than decimal, and this too must be converted, this time back to the decimal system.
Digital electronics is a “logical” science. Logic, generally speaking, is the science of formal principles of reasoning. Digital logic is the science of reasoning with numbers; a special circuit called a gate can perform nearly all-digital functions.
If the logic operation is plex for one gate, it can almost always be implemented through the use of bination of gates. These extended logic circuits are binational logic.
A register is a group of flip-flops with each flip-flop capable of storing one bit of information. An n-bit register has a group of n flip-flops and is capable of storing any joinery