Troubleshooting electronic circuits: Debugging and improving your DIY projects and experiments

About the Author
Title Page
Copyright Page
Contents
Preface
Acknowledgments
1 Introduction
	Goals of this Book
	Quick Notes: Replacing Electrolytic Capacitors and Soldering
	Soldering Problems (Cold Solder Connections)
	Summary
2 Basic Breadboards
	Solderless Breadboards
		Quality
		Power Buses on Solderless Breadboards . . . Look for Breaks in the Power Bus Lines
		And Now Some Words of Caution
	Other Breadboards
3 Power Sources: Batteries and Battery Holders, Safety Issues, and Voltmeters
	Batteries
		Again, a Word of Caution
		Expected Battery Capacity
		Safety Considerations
	Survey of Digital Voltmeters
4 Some Basic Electronic Components
	Capacitors
		Radial and Axial Electrolytic Capacitors
		Measure Twice, Install Once: Erroneously Marked Capacitors
	Resistors
		Using a DVM to Measure Resistance Values
		Measuring Low Resistance Values
5 Diodes, Rectifiers, and Zener Diodes
	Diodes and Rectifiers
	Forward Voltage Across Anode to Cathode and Reverse Voltage Effects
	Testing Diodes and Rectifiers with Digital and Analog Volt Meters
	Schottky Diodes
	A Brief Look at Zener Diodes
	Some General Rules About Diodes
6 Light-Emitting Diodes
	The LED’s Light Output
	LED “Minimum Turn On” Voltages
	Other Types of Green LEDs
	Problems with Paralleling Two LEDs with Different Turn-On Voltages
	Protecting LEDs from Damage Due to Reverse Voltage Across the Anode and Cathode
	Some Keys Points About Light Emitting Diodes
7 Bipolar Junction Transistors
	Bipolar Junction Transistors
	What Happens When a Transistor Is Damaged
	Schematic Symbol of NPN and PNP Transistors
		Applying a DC Voltage to the Base of the Transistor to Provide a Constant Current Source
	Improved Current Source Circuits
	What Happens When Things Go Wrong
	Insufficient “Headroom Voltage” for the Transistor
	Sometimes Even a Correct Circuit Goes Bad
	Summary
8 Troubleshooting Discrete Circuits (Simple Transistor Amplifiers)
	Important Practical Transistor Specifications
	Simple Transistor Amplifier Circuits
	First DC Analysis: Capacitors = Batteries with Self Adjusting Voltages
	Second DC Analysis: Take Out the Capacitors to Find the DC Currents and DC Voltages
	Finding the AC Signal Gain
	Limited Input Amplitude Range
	Output Swing Determined by IC and RL || R2
		Troubleshooting the One-Transistor Amplifier
	Using Negative Feedback to Build “Mass Production” Amplifiers
	DC Analysis of Self-Biasing Amplifier
	AC Analysis of a Self-Biased Amplifier
	Output Resistance Ro'
	Another Common Emitter Amplifier
		Troubleshooting the Amplifier in Figure 8-31
	Maximum Output Voltage Swing
		Amplifier’s Emitter AC Grounded via CE
		Amplifier’s Emitter Partially AC Grounded via Series RE2 and CE2
	Finding an Optimum Bias Point for Maximum Output Swing with Just an Emitter Resistor
	Summary
9 Analog Integrated Circuits Including Amplifiers and Voltage Regulators
	Operational Amplifiers
		Maximum Safe Power Supply Voltage
		Minimum Power Supply Voltage
		Caution on Providing Supply Voltages
		Maximum Output Current
		Output Voltage Range
		Input Signal Range
		Non-Inverting Gain Amplifiers
		Inverting Gain Amplifiers
		A Short Look at Linear Voltage Regulators
		Drop-Out Voltage Summary
		Voltage Selections, Packages, Pin Outs and Schematics
		Knowing the Pin Out Sequence Is Important
		Low–Drop-Out Voltage Regulators
10 Audio Circuits
	Preamps and Power Amps
	A Basic Difference Amplifier
		Dynaco PAT-5 Low-Level Preamp Section and Power Supply
	Preamp’s DC Bias Point Estimates
	AC Analysis
	A High-Fidelity Audio Power Amplifier
	DC Biasing Conditions in Figure 10-9
	AC Signal Conditions
11 Troubleshooting Analog Integrated Circuits
	Circuits That Need Fixing or Redesigning
	Photodiode Circuits
	Trans-resistance Amplifiers
	Summary
		Reference Books
12 Some Ham Radio Circuits Related to SDR
	Software Defined Radio Circuits
		Some Troubleshooting Tips Concerning Figure 12-5 and Figure 12-7
	A Common Sample-and-Hold RF Mixer Circuit
	A Preferred Implementation with Sample-and-Hold Circuits
	A Cool Four-Phase Commutating Mixer
	DC Bias Conditions
	Testing Circuit with an RF or Function Generator
	Improving the “Original Design”
	Another View of Op Amp Circuits (Where the Inverting Input Drives a Load)
	Suggested System Approach
	Crystal Oscillators
	Types of Crystals
	Low-Frequency Cylindrical Crystals, “Standard” Crystals, and Ceramic Resonators
	Standard HC-49 and High-Frequency Cylindrical Crystals
	Ceramic Resonators
		Be Aware of Overtone Crystals
	Gain Bandwidth Product Revisited
	Summary
13 Timer, CMOS, and Motor Drive Circuits
	Types of 555 Timer Chips
	Basic Modes of the 555 Timer Chip and Pin Outs
	The 555 Pulse Generator (a.k.a., One-Shot or Monostable Mode)
		Troubleshooting the 555 One-Shot Monostable Timer
	When You Want to AC Couple a Signal to Trigger a Pulse Output Signal
	“Strange” Output Signals Observed via an Oscilloscope
	Troubleshooting the 555 Oscillator (a.k.a. Astable Mode)
	One More Example on Driving Speakers with the 555
	Why Again an Output Coupling Capacitor Is Preferable
	Using a 555 to Drive Motors via Pulse-Width Modulation
	Summary of Troubleshooting Techniques
14 Troubleshooting Other Circuits, Including Kits and Projects
	Component Kits and Test Equipment
	LED and Sensor Kits
	A Quick Detour with the LM386 Audio Power Amplifier IC
	Photonics: A Light Transceiver System
	Thermal Sensing Circuit via Thermistor (Temperature-Dependent Resistor)
	A Circuit Using an Electrolytic Capacitor Incorrectly
	Identifying and Fixing “Bad” Circuit Designs
	An Example of the Missing Ground Connection
	Ferrite Beads to Tame Parasitic Oscillations
	Summary
15 More Tips and Final Thoughts
	Deciphering Schematics with Too Many Connection Flags
	Troubleshooting with Minimal Test Equipment
		Analog Meter Driving Circuits for AC Signals
		Troubleshooting an Older Push Pull Audio Amplifier in a 1950s Transistor Radio
		Reducing Noise on the Power Supply Bus with Multiple Circuits
		Bad Connections from Some IC Sockets
	Summary and Final Thoughts
A Choosing Test Equipment
	Lab Power Supplies (Adjustable)
	Signal Generators
	Oscilloscopes
	Examples of Display Resolution and Number of Memory Points
	Oscilloscope Probes
	An Inexpensive Lab
B Online Learning Resources
C Components and Parts Suppliers
	General Electronic Components
		Transistors, FETs, Diodes, LEDs, Photodiodes, and ICs
		Low-Noise Transistors and JFETs, Including Matched Pairs
		Passive Components, Resistors, Capacitors, Fixed Valued Inductors, Transformers, Tools, Soldering Irons, Breadboards, and Solder
		Kit Parts for Transistors, Diodes, Capacitors, Resistors, LEDs, and More
	Ham Radio Parts
		Crystals, Inductors, Capacitors, Transistors, RF Transistors, Transformers, and ICs
		Oscillator Coils, IF Transformers, and Audio Transformers
		Antenna Coils
		Variable Capacitors
	Science Kits, Cool Things, and Everything Else
Index