Electrical Engineering

Armature Winding : The complete assembly of conductors carried on the armature and connected to the commutator or to the terminals of the machine is called a r mature winding. field winding :   field coil: the electric coil around a field magnet that produces the magneto motive force to set up the flux in an electric machine.

All sheets of microprocessor sessional

8259A PROGRAMMABLE INTERRUPT CONTROLLER 8086, 8088 Compatible MCS-80, MCS-85 Compatible Eight-Level Priority Controller Expandable to 64 Levels Programmable Interrupt Modes Individual Request Mask Capability                               Single a5V Supply (No Clocks) Available in 28-Pin DIP and 28-Lead PLCC Package (See Packaging Spec., Order #231369) Available in EXPRESS    Standard Temperature Range Extended Temperature Range

 Armature reaction:           By Armat u re reaction is meant the effect of magnetic field set up by armature current on the distribution of flux under main poles of a generator.The armature magnetic field has two effects : It demagnetizes or weakens the main flux. It cross-magnetizes or distorts it .                                                 

  General purpose of registers : General purpose registers are basically used to hold temporarily data and intermediately result. example: ax,bx,cx,dx each of 16 bits. whereas special purpose register are primly used for memory access. It is of two types:  1. segment register and  2. index register/ pointer

    Programmable Interval Timer- 8254 The 8254 is a programmable interval timer/counter designed for use with Intel microcomputer systems.It is a general purpose, mulch-timing element that can be treated as an array of I/O ports in the system software.The 8254 solves one of the most common problems in any microcomputer system, the generation of accurate time delays under software control. Instead of setting up timing loops in software, the programmer configures the 8254 to match his requirements and programs one of the counters for the desired delay. After the desired delay, the 8254 will interrupt the CPU. Software overhead is minimal and variable length delays can easily be accommodated.

8255 Programmable Peripheral Interface (PPI) Intel 8255A is a general purpose parallel I/O interface. The peripheral devices are slower than the microprocessor. PPI makes an inter-relation between microprocessor and peripheral devices. It provides three I/O port (Port A, Port B and Port C) and can be programmed as a) Simple Parallel I/O (No handshaking) b) Simple Strobe I/O (Use STB handshake) c) Single Handshake I/O (Use STB-ACK handshake) d) Double handshake I/O (Uses STB-ACK and STB-ACK) Handshaking and Handshaking Signal The making of inter relation between slower peripheral device and microprocessor is called handshaking. Before making the inter-relation between peripheral device and microprocessor the PPI send some signals to microprocessor and peripheral device to perform the process, these signals are called handshaking signal. 8255-based devices that perform handshaking support four handshaking signals: • Strobe Input (STB) • Input Buffer Full (IBF) •