mith College Computer Science CSC270 Spring 16 Circuits and Systems Lecture Notes Week 3 Dominique Thiébaut dthiebaut@smith.edu
Crash Course in Electricity and Electronics
Zero Physics background expected!
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Main Concepts: Difference in Potentials vs. Intensity
An Analogy Hoover Dam http://www.history.com/topics/hoover-dam
An Analogy Hoover Dam http://www.history.com/topics/hoover-dam Difference in Potentials Intensity
An Analogy Hoover Dam http://www.history.com/topics/hoover-dam Difference in Potentials Resistance Intensity
An Analogy Hoover Dam http://www.history.com/topics/hoover-dam Difference Resistance in Potentials Intensity =0
An Analogy Hoover Dam http://www.history.com/topics/hoover-dam Difference in Potentials Intensity
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Observations Resistance Intensity Resistance oo x Intensity 0 High difference in potentials Intensity Low difference in potentials Intensity
Observations Resistance Intensity Resistance oo x Intensity 0 High difference in potentials Intensity Low difference in potentials Intensity
Observations Resistance Intensity Resistance oo x Intensity 0 High difference in potentials Intensity Low difference in potentials Intensity
Observations Resistance Intensity Resistance oo x Intensity 0 High difference in potentials Intensity Low difference in potentials Intensity
Observations Resistance Intensity Resistance oo x Intensity 0 High difference in potentials Intensity Low difference in potentials Intensity
Another Analogy
Another Analogy Difference in Pressure
Another Analogy Difference in Pressure No resistance in the pipe no difference in pressure
Another Analogy Resistance Difference in Pressure
Another Analogy Resistance Difference in Pressure
Observations Keeping Intensity constant, Resistance Difference in Potentials
+ - R
+ - R
I current Power Supply + - V voltage R Resistance Ground
Assumptions An electrical wire has no resistance A closed switch has no resistance An open switch has infinite resistance The current flowing in a closed-loop circuit is the same everywhere.
I current Power Supply + - V voltage R Resistance Ground
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Ohm s Law Voltage = Resistance * Intensity V = R. I
Ohm s Law Voltage = Resistance * Intensity V = R. I Volt Ohm Amp V Ω A
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
What is I? I 5V + - V voltage R 1 KΩ Ground
What are I, I1, I2? I 5V + - I2 R2 1 KΩ I1 R1 1 KΩ Ground
What is I? 5V + - I R1 1 KΩ R2 4 KΩ Ground
What are V1, V2? 5V + I V1 R1 1 KΩ - V2 R2 4 KΩ Ground
What are V1, V2? 5V + I V1 R1 1 KΩ - V2 R2 4 KΩ Ground
What is I? 5V + - R1 3 KΩ R2 7 KΩ I Ground
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
What does R look like?
http://www.sysrecon.com/wp-content/uploads/2014/07/resistorcolorchart.png
What values?
Simplification I 5V + - V voltage R 1 KΩ Ground
Simplification +5V R 1 KΩ
How Does that Apply to Us? 1 x
How Does that Apply to Us? +5V 1 x x
We stopped here last time
How Does that Apply to Us? x 0
How Does that Apply to Us? x 0 x 0
Exercise +5V 2-to-4 A1 Y0' Y What is Y(a)? a A0 Y1' NC Y2' NC E' Y3' NC
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Meet The Diode
Diode = semiconductor http://dictionary.reference.com/browse/english
R1 1 KΩ + - P N
R1 1 KΩ + - P N
R1 1 KΩ + - N P
R1 1 KΩ + - N P
Symbol R1 1 KΩ + - P N
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Meet the Transistor
R1 1 KΩ C + - N P N B R2 10 KΩ + - E Collector Base Emitter
R1 1 KΩ C + - N P N B R2 10 KΩ + - 0 V E Collector Base Emitter
R1 1 KΩ C + - N P N B R2 10 KΩ + - E Collector Base Emitter
R1 1 KΩ C + - N P N B R2 10 KΩ + - 5 V E Collector Base Emitter
Symbol R1 1 KΩ + C B R2 - E 10 KΩ + - Collector Base Emitter
Symbol R1 1 KΩ + C B R2 - E 10 KΩ + - Collector Base Emitter
What is f(a)? Quiz 1 KΩ a 08 10 KΩ f 2N2222
A Real TTL Circuit http://www.allaboutcircuits.com/textbook/digital/chpt-3/not-gate/
A Real TTL Circuit http://www.allaboutcircuits.com/textbook/digital/chpt-3/not-gate/
A Real TTL Circuit http://www.allaboutcircuits.com/textbook/digital/chpt-3/not-gate/
A Real TTL Circuit http://www.allaboutcircuits.com/textbook/digital/chpt-3/not-gate/
What is h(a,b)? Quiz 1 KΩ 1 KΩ a b 10 KΩ 10 KΩ h
Hydrodynamic Analogy Outline Resistance, Intensity, Difference in Potentials Ohm's Law Exercises: solving electrical circuits Resistors Diode Transistor Practical Circuits
Practical Design Rules for Discrete Parts
Input Switch 1 KΩ
Logic Indicator R 04
Logic Indicator What s a good value? R 04
Logic Indicator What s a good value? R 04