Binary Division - Main points to write

• Division is continued subtraction till remainder is less than divisor
• D Flip flops are used as PIPO registers
• For full adder, carry out = 1, if remainder > divisor, ie, continue continued subtraction
  Cout = 0, if remainder < divisor, ie, end the process

Transfer Characteristics Of TTL

Note : In the diagram below, at the third part, Q2 in ON, not OFF

Race Around Condition

Static & Dynamic Resistances Of Diodes

Static : DC Resistance. Measured by considering V & I of a single point
Dynamic : AC Resistance, measured by considering a small change in the values of v & i. Take 2 points and the difference in the values of V, I while calculating.

To determine reverse saturation current of diode

Obtain the forward characteristics of the diode. Note any V & I after the knee voltage.
Substitute in equation;

I = Io(e^(V/nVT) - 1 )
n = 1 for Ge, 2 for Si
Vt = 26mV

Find reverse saturation current !

Or reverse bias the diode & determine the current flowing through using uA

0-1-1-1-3-4-5-7 Synchronous Sequence Generator - Method 2

Proteus File

Octal Counter Using 7490 ( 74LS90 )

PROTEUS FILE

Octal Counter - 74LS93

PROTEUS FILE

9-27 COUNTER

Tips : If Rs of second counter R1,R2 are set to high, output will be 9
If Rs of first counter are set to high, output will be 0;

Circuit needs initial setting to 9; using the third logic gate as high ( third from top )

Proteus File

Circuit :

4:2 High Priority Encoder

Truth table :

Expressions :

s1 = d2+d3

                 

s0 = d3+d2d1

Proteus File

Diagram :

Asynchronous 0-2-4-5 counter

Hint : Design Mod 4 async counter, and force the outputs to required states,
ie, 00 -> 000
01 -> 010
10 -> 100
11 -> 101

Proteus File ( Incase of error with clock, just replace the clock with the same part and it should work fine )

8 Bit adder

Just add the digits back to back with corresponding priorities

Proteus File

0-1-1-1-3-4-5-7 Synchronous Pattern Generator

Hints :
No of flip-flops required JK 7476 : 5
No of flip-flops whose outputs are taken as output of circuit : 3 ( The least significant 3 digits )

T5,T4,T3,T2,T1 : Inputs of Flipflops
D5,D4,D3,D2,D1 : Outputs ( D3-D1 : Output of the circuit )

t5 = d4+d5
                      
t4 = d5d3d2d1

t3 = d2
                             
t2 = d5+d2+d3d2d1
               
t1 = d2d1+d2d1

Note : Expressions may be further simplified using K-map

Proteus 8 Simulation File : Download

Circuit Diagram :