1. Introduction to Digital Electronics

2. DC
An electrical current can flow in either of two directions. If it flows in only one direction, it is called direct current (DC).
A battery is an example of a DC voltage that can supply DC current!
Electrical engineers also use the term DC to refer to an average (or constant part of) a voltage or current signal.

3. AC
A current which alternates in direction or polarity is called an alternating current (AC).
The current flowing from a wall outlet is an example of an AC current!
DC voltage, RMS Voltage, Frequency, Period

4. Resistors

5. Resistor Color Code

6. Voltage Divider +VDD = Use Ohm’s Law, KCL, KVL!
I2= 5 / (15K) = 0.33 mA
I1= VDD / (R1 + R2) = 0.33 mA
I1= 5 / (15K) = 0.33 mA
Vout = [R1 / (R1 + R2)] * VDD
Vout = 5/3 Volts

7. Capacitors
There are many kinds of capacitors but they all do the same thing: store charge.
The simplest kind of capacitor is two conductors separated by an insulating material.

8. Diodes
A diode is like and electronic one-way valve. It will allow current to flow in only one direction! Clearly, diodes can be used to convert AC currents to DC!

9. Transistors
Transistors are three terminal devices. A very small current or voltage at one terminal can control a much larger current flowing between the other two leads.

10. Operational Amplfier
Operational Amplifiers take small voltages and make them MUCH larger.
Golden Rules (Op amp with negative feedback):
No-current flows into either (+) or (-) inputs.
The (+) and (-) inputs are at the same voltage.

11. Digital Signals
A digital signal can take on only one of two voltages: 0 Volts and 5 Volts.
The Handy Board treats 0 Volts as logical TRUE and the 5 Volt signal as logical FALSE.
5 Volts
0 Volts

12. Analog Signals
An analog voltage can take on any value between 0 and 5 Volts. An Analog-to-Digital Converter (ADC) within the Handy Board will, however, will quantize the analog signal. The HandyBoard ADC is 8 bits wide.

13. Gates The most basic digital devices are called gates.
Gates got their name from their function of allowing or blocking (gating) the flow of digital information.
A gate has one or more inputs and produces an output depending on the input(s).
A gate is called a combinational circuit.
Three most important gates are: AND, OR, NOT

14. Digital Logic
Binary system -- 0 & 1, LOW & HIGH, negated and asserted.
Basic building blocks -- AND, OR, NOT

16. ECE 301 - Digital Electronics
Numbers
ECE Digital Electronics

17. ECE 301 - Digital Electronics52
What does this number represent?
What does it mean?
ECE Digital Electronics

18. ECE 301 - Digital Electronics
What does this number represent?
Consider the base (or radix) of the number.
ECE Digital Electronics

19. ECE 301 - Digital Electronics
Binary Addition
Sum
Carry
ECE Digital Electronics

20. ECE 301 - Digital Electronics
Binary Addition
Examples:
ECE Digital Electronics

21. ECE 301 - Digital Electronics
Binary Subtraction
Difference
Borrow
ECE Digital Electronics

22. ECE 301 - Digital Electronics
Binary Subtraction
Examples:
ECE Digital Electronics

23. Binary Multiplication
x x x x 1
Product
ECE Digital Electronics

24. Binary Multiplication
Examples: x x
ECE Digital Electronics

25. DeMorgan’s Theorems
Digital Electronics 
2,1 Introduction to AOI Logic
DeMorgan’s Theorems
DeMorgan’s Theorems are two additional simplification techniques that can be used to simplify Boolean expressions. Again, the simpler the Boolean expression, the simpler the resulting logic.
Introductory Slide / Overview of Presentation
Project Lead The Way, Inc.
Copyright 2009

26. DeMorgan’s Theorem #1 Proof 1 1
DeMorgan’s Theorems
Digital Electronics 
2,1 Introduction to AOI Logic
DeMorgan’s Theorem #1
Proof
Overview & proof of DeMorgan’s Theorem #1 1 1
The truth-tables are equal; therefore, the Boolean equations must be equal.
Project Lead The Way, Inc.
Copyright 2009

27. DeMorgan’s Theorem #2 Proof 1 1
DeMorgan’s Theorems
Digital Electronics 
2,1 Introduction to AOI Logic
DeMorgan’s Theorem #2
Proof
Overview & proof of DeMorgan’s Theorem #2 1 1
The truth-tables are equal; therefore, the Boolean equations must be equal.
Project Lead The Way, Inc.
Copyright 2009

28. Thank You
Created By – Prof. Swapan Kumar Gupta
SHD College,Pathankhali