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number-systems, Digital electronics, A.(A+B), ANY LOGIC (TRUTH TABLE) CAN…
number-systems
Base and place value
Better and easier
decimal (indo arabic)
hexadecimal base 16
octal base 8
binary base 2
How to inter convert and perform operations
understand and recall decimal system then connect the others
Specific technique for base 2to n power
Idea of Bits
Group bits
Break into group of bits or bits
Think of them as a building block
new symbol for new numbers
Digital electronics
Boolean algebra
Very similar to set theory but not the same
Find how different from set theory
Use of truth table
For proof
True equal 1
False 0
Operations on bools
Or a+b
Not ā
And a.b
Universal operation/gates
NOR
NAND
XOR
Laws
Important
A+1=1
A +A.B =A
Distributive law 2
A + B.C = (A+B).(A+C) proof use
Given the truth table for a boolean function can you get the expression
Yes two ways
Use boolean laws
Kaunaugh maps
Its map of the min ormax terms
note that you can in pricple find the pos expression from the karnaugh map of the min terms
if f function
f complement t
truth table invert
2 more items...
adjacent expressions must have something in common
WHY becuz we need to use idea of pairs, quad etc.
order of the column and row names matters
rows
from top to bottom
colums
from left to right
WHY
i think so it doesn't matter maybe just convention ? to just start with 00 but the order changes to accomodate the adjacent criteria
WHY you should use this and what it does ?minimize the number of gates or equivalently the terms in the sop or pos to implement a logic(truth tabel )
simplify and reduce the SOP OR POS
Simplify
Exp involving minterms
Make a map of minterms
Exp involving max terms
Make a map of max terms
Group the 0
Why
1 more item...
Why adjacent
In case max
In case of min
Which things I can combine
Last and first of row
Don't learn the cases
Learn why combine and how
Idea
Always combine in powers of two
Why
Its not magic it is the boolean laws only
always take the maximum number of common squares even if some squares are common
note that we are allowed to overlap as long as all the squares are not common in the two groups
maximize the size of each group
Express the result an SOP or POS of the inputs
Always a unique expression NO
A.(A+B)
ANY LOGIC (TRUTH TABLE) CAN BE REPRSENTED
POS
Product (intersection)of any number of items false if at least one is false
Exclusivity of sum for being false at a time only one can be false
each possible sum which involves all the inputs is called the max term
how many max terms possible
SOP
important Exclusivity of the products for being true at a time only one will be true
each possible product involving all the inputs is called the min term
Idea union (or) of any number of items will be true if any one of them is true
SEMICONDUCTORS
BJT WHAT IS BIPLOAR , JUNCTION ,TRANSISTOR
RELATIONS ALPHA BETA ARE THEY VALID FOR BOTH NPN OR PNP
Thickness c>e>b
Why
More heat generated in collector so inc surface area to dissipate it
Heat generated depends on the power power =vi so now v across the collector is very high at almost all the emmitter current goes through the collector
Doping e>c>b
Configrations in which we can connect it in a circuit
DIFFERENCE
Ask do we need to remember the qualitative summary of bjt configrations
BJT CURRENTS
Directions are very important
All the relationships between the currents depend on the direction
ICBO
Collector to base leakage current with emiitet open circuit
Reverse saturation current
ICEO DOUBT
Characteristics note only DC BEHAVOIUR
Input
Output characteristics
Vary one thing only
But what can you vary voltage only
Because only DC input and output voltages are dc
Input or output depend configration of tranisi
HOW DO I MAKE SURE THAT THE TRANISITORS I MAKE WITH SOME FINITE PROBABILITY OF ERRORS TO HAVE SIMILAR OR SAME CHRACTERISTICS
PROBLEM
MANUFUCATURE TRANSISITOR
beta make not remain constant
HOW TO SOLVE IT
solution
we want ouput nearly independent beta
we use self biasing circuit
WHAT FACTORS DETRERMINE THE CHARCTERISTICS
INPUT VOLTAGE
OUTPUT CHAR
OUTPUT CURRENT
BEACUSE OUT VOLTAGE IS OUTCURREDNT* LOAD
IT DEPENDS ON THE IF iIc ouput currengt
depnds ib
with beta B
BIASING VOLTAGES
beta depnds
B OR aplha
beta alpha depnd on the manfacturing of ttrab=nsitor
bascially depned on ratio of carriers reaching collectkr vs base
Semiconductor diode
Pn junction diode
Diffusion
Drift
Reverse
Small drift current which is independent of the voltage
Potential barrier
Forward
Diffusion current increase exponentially as the dec of potential barrier
Voltage across diode constant WRONG
Voltage maximum is fixed but voltage not constant
P has to be at higher potential than n but not more than a maximum like Si 0.7
Application
Rectifier
Full wave
Bridge
Centre tap
keep in min the voltage
Avg voltage
Half wave
Avg voltage
avg current
assuming ideal diode
if not assume that load includes the diode resistance
Capacitor filter
Ripple voltage
For finding take approximation of the time constant vs time period
finding the required capacitance
assuming RL >>>>>T
Different modes in which it can operated
Why
Because two diodes therefore 4 combinatione
MODES of operation (related to biasing )