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Tuesday, 6 August 2013

Typical Bipolar Transistors

Typical Bipolar Transistors

 

  • AC127

    Germanium audio output transistor - found in vintage radios, and in some more modern circuits where sensitivity to heat is required.
  • BF318

    Silicon Video amplifier transistor uses a collector/emitter voltage (VCE) of about 150V and will amplify frequencies up to 80MHz
  • BU208A

    Silicon output transistor used in TVs and large screen monitors. Can deliver high power and withstand pulse VCE voltages of about 1000V. The metal case (normally bolted to a heat sink) is the collector connection.
  • BD124

    Silicon TV output transistor with a lower power rating.
  • BC108

    General purpose Silicon voltage amplifier transistor, the silver case with a small tab to identify the emitter connection is a standard TO39 package.
  • BD 131

    Silicon audio NPN output transistor in a TO26 package for mounting on a suitable heat sink, will dissipate 15W and is often used as part of a push-pull pair with a matched BD132 PNP transistor.

 

Saturday, 3 August 2013

Aeronautical Development Agency (ADA) - Project Engineers (PE) - BE/BTech - ME/MTech

Aeronautical Development Agency (ADA) is hiring BE BTech holders for Project Engineers role

Company name : Aeronautical Development Agency
Posts : Project Engineers
Qualification : BE BTech
Location : Bangalore
Last date to apply : 31/08/2013


Friday, 2 August 2013

VERILOG TASK AND FUNCTIONS - SYNTAX - EXAMPLE



                Task and Functions in verilog are similar to each other but has many differences in their operation. These can be used to do a simple operations that can be called repeatedly, but instead of instantiating a module, these could be used. Here is the syntax and example for the Verilog Task and function. 

Wednesday, 17 July 2013

Administrative Officers (Scale-I) - NATIONAL INSURANCE COMPANY LIMITED - ONLINE Recruitment

Welcome to Online Recruitment for the post of Administrative Officers (Scale-I)


 


Important Dates

Friday, 12 July 2013

VERILOG DATATYPES AND OPERATORS - SYNTAX - EXAMPLES

DATATYPES:
          The datatype denotes the type of the data assigned & processed by the variable. But in Verilog it exactly specifies the output type, such as a storage or non-storage type.
          The different datatypes in verilog are as follows
NETS
wire
Establishes connectivity, with no logical behavior or functionality implied.  (within non-procedural statements only)
tri
Establishes connectivity, with no logical behavior or functionality implied. This type of net has the same functionality as wire, but is identified distinctively to indicate that it will be three-stated in hardware.
wand
A net that is connected to the output of multiple primitives. It models the hardware implementation of a wired-AND, e.g., open collector technology.
wor
A net that is connected to the output of multiple primitives. It models the hardware implementation of a wired-OR, e.g., emitter coupled logic.
supply0
A global net that is connected to the circuit ground.
supply1
A global net that is connected to the power supply.
tri0
A net that is connected to ground by a resistive pull-down connection.
tri1
A net that is connected to the power supply by a resistive pull-up connection.
trireg
A net that models the charge stored on a physical net.

REGISTERS
reg
Register variables are assigned values by procedural statements within an always or initial block. REG variables can only be output.

Register variables hold their value until an assignment statement changes them. The following are predefined register types: reg, integer (32 bit, 2s complement), real (double precision 64bit), realtime, and time (for time related functions).

MEMORIES
       Verilog does not have separate datatype for memory array. But can be used from other data type reg
SYNTAX:      reg  [word_size]   <variable>[array_size];

STRINGS
       Verilog does not have a distinct data type for strings. Instead, a string must be stored within a properly sized register by a procedural assignment statement. A properly sized reg (array) has 8 bits of storage for each character of the string that it is to hold.

SYNTAX:      reg [8*num_char-1: 0] string_holder;

CONSTANTS
A constant in Verilog is declared with the keyword parameter, which declares and as- signs value to the constant. The value of a constant may not be changed during simulation. Constant expressions may be used in the declaration of the value of a constant.
SYNTAX:     parameter <variable> = <value>;

EXAMPLES
wire out1;
"out1" is a wire that only outputs
reg out2;
 "out2" is a register; it stores and outputs a value
reg [7:0] out3;
"out3" is a 8-bit register
reg [15:0] out4[7:0];
 "out4" is a 8-bit register array from 0 to 7
 Scope of a variable:

          The same net type is not referenced exactly the same within module, task, function. The flow is as given in the figure,

 OPERATORS:
          Operators in Verilog are the same as they are in other programming languages. They take two values and compare (or otherwise operate on) them to yield a third result. The following table briefs the operator and its examples.
Operator
Argument
Result
Arithmetic
Pair of operands
Binary word
Bitwise
Pair of operands
Binary word
Reduction
Single operand
Bit
Logical
Pair of operands
Boolean value
Relational
Pair of operands
Boolean value
Shift
Single operand
Binary word
Conditional
Three operands
Expression

OPERATOR TYPE
OPERATOR SYMBOL
OPERATION PERFORMED
EXAMPLE


Arithmetic
*
Multiply
x= a*b

/
Division
x= a/b

+
Add
x= a+b

-
Subtract
x= a-b

%
Modulus
x= a%b

+
Unary plus
x= a+b

-
Unary minus
x= a-b

Logical
!
Logical negation
!a

&&
Logical and
a && b

||
Logical or
a || b

Relational
Greater than
a>b

Less than
a<b

>=
Greater than or equal
a>=b

<=
Less than or equal
a<=b

Equality
==
Equality
a == b

!=
inequality
a != b

===
CASE equality
a === b

(includes x,z in bit-by-bit basis)

!==
CASE inequality
a !== b

(includes x,z in bit-by-bit basis)

Reduction
~
Bitwise negation
x= ~a

~&
nand
~&a

|
or
x= |a

~|
nor
x= ~|a

^
xor
x= ^a

^~
xnor
x= ^~a

~^
xnor
x= ~^a

Shift
>> 
Right shift
x= a>> n

<< 
Left shift
x= a<< n

Concatenation
{ }
Concatenation
x= {a,b,n}

x={a[3:0],b,a[7:4]}

Conditional
?
conditional
x= a<b?1:0

 
OPERATOR PRECEDENCE
Sign complement
HIGHEST
Multiplication Division Modulus
|
|
|
|
|
|
V
Addition Subtraction
Shift
Relational
Reduction
Logical
Conditional
LOWEST
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