1
ECTE290
Spring 2007
Lecture 11
2
Last Week
±
Closed Loop OpAmp
V
POS
–V
NEG
r
in
=
∞
–
V
neg
<
V
OUT
<
V
pos
Currents
i
+
and
i
−
to (or from) input terminals are zero
V
+
= V
i
+
= 0
i
= 0
Defines the
Linear Region
of operation
Virtual short
Virtual open
1. i
in
=0
Assumptions for analysis of ideal
2. V
+
=V

opamp with negative feedback
feedback
3
This Week
±
Number Systems
±
Binary number
±
Hexadecimal number
±
Binary arithmetic
±
Signed binary numbers
±
Logic Gates & Truth Tables
±
Boolean Algebra
4
Numbering Systems
±
We use the decimal numbering system
±
10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
±
For example: 12
±
All computers use the binary numbering system
±
Only two digits: 0, 1
±
For example: 10, 10001, 10110
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Similar to decimal, except uses a different base
±
Binary (base2): 0, 1
±
Decimal (base10): 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
±
Octal (base8): 0, 1, 2, 3, 4, 5, 6, 7
±
Hexadecimal (base16): 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
A, B, C, D, E, F (A=10, .
.., F=15)
±
What do we mean by a base?