Table of Content


Issue 1 Sept 2009 

Back of the Envelope Calculations 

  - 

Wind Energy Ship

Circuit Diagnosis

  - 

Exploding Capacitors

Dave's Rants & Raves

  - 

Electrodeless Fluorescent Lamps

Experimenter's Corner

  - 

Wireless Battery Charger

Good Idea done Badly

  - 

Bad Solar Powered Birdbath Design

What the World needs Now

  - 

Drinking Fountain from Pond Water

Wily Widget, the Lone Inventor

  - 

Wave Length Indicator

 

Issue 2 Oct 2009

Back of the Envelope Calculations

  - 

Shippable Energy Container

Circuit Diagnosis

  - 

Vapor Pumping

Dave Rants

  - 

Electrodeless Fluorescent Lamps

Experimenter's Corner

  - 

Light Powered Battery Charger

Good Idea done Badly

  - 

Bad Path Light Design

New Products, 2008

  - 

New Products, 2008

What the World needs Now

  - 

PIGEON SCARECROW

Wily Widget, the Lone Inventor

  - 

Fence Alarm

 

Issue 3 Nov 2009

Back of the Envelope Calculations

  - 

Supercapacitor Home Energy Storage Unit

Circuit Diagnosis

  - 

Connector Woes

Dave Rants

  - 

Hot Rock Geothermal Energy

Experimenter's Corner

  - 

NiMH Battery State of Charge Monitor

Good Idea done Badly

  - 

Bad Alarm Clock

New Products, 2008

  - 

New Products, 2008

What the World needs Now

  - 

Drinking Water from Thin Ai

Wily Widget, the Lone Inventor

  - 

Vertically Lifting Security Gate Power Source

 

Issue 4 Dec 2009 

Back of the Envelope Calculations

  - 

Aluminum Pop Can Energy Source

Circuit Diagnosis

  - 

Flaky Garage Door Opener

Dave Rants

  - 

Bad Chinese Capacitors

Experimenter's Corner

  - 

Magnetic Vehicle Motion Sensor

Good Idea done Badly

  - 

Bad Office Chair Wheels

New Products, 2009

  - 

New Products, 2009

What the World needs Now

  - 

Wind Power Monitoring Blimp

Wily Widget, the Lone Inventor

  - 

Fireplace Fizzle

 

Issue  5 Jan 2010

Back of the Envelope Calculations

  - 

Energy Savings Using Voltage Bucking Transformer

Circuit Diagnosis

  - 

Dirty PC Boards

Dave Rants

  - 

Yellowstone Might Explode

Experimenter's Corner

  - 

Measuring Low Value Resistors

Good Idea done Badly

  - 

Bad Computer Power Supplies

New Products, 2009

  - 

New Products, 2009

What the World needs Now

  - 

NiMH Battery Tester

Wily Widget, the Lone Inventor

  - 

Solar Powered Wireless Sensor

 

Issue 6 Feb 2010

Back of the Envelope Calculations

  - 

Long Life Solar Powered LED Light

Circuit Diagnosis

  - 

Motor Speed Controller

Dave Rants

  - 

Inventor Name Fraud

Experimenter's Corner

  - 

Long Range Motion Sensor

Good Idea done Badly

  - 

Disappearing Letters on Key Boards

New Products

  - 

New Products

What the World needs Now

  - 

Tritium Power Generator

Wily Widget, the Lone Inventor

  - 

Coin Operated Telescope

 

Issue 7 Mar 2010

Back of the Envelope Calculations

  - 

Back of the Envelope Calculations

Circuit Diagnosis

  - 

Wrong LED Wavelength

Dave Rants

  - 

Fading White LEDs

Experimenter's Corner

  - 

White LED Lifetime Tests

Good Idea done Badly

  - 

Another Bad LED Night Light

New Products

  -  

New Products

What the World needs Now

  - 

Long Lasting LED Night Light

Wily Widget, the Lone Inventor

  - 

High Power Flashing LED

 

Issue 8 Apr 2010

Circuit Diagnosis

  - 

PCB Fabrication Problems

Dave Rants

  - 

Strange Science

Experimenter's Corner

  - 

Charging Alkaline Batteries

Good Idea done Badly

  - 

Bad Fluorescent Night Light

New Products

  - 

New Products

What the World needs Now

  - 

Candle Flame Powered Battery Charger

Wily Widget, the Lone Inventor

  - 

Corona Monitor

 

Issue 9 May 2010

Back of the Envelope Calculations

  - 

Hydrogen Energy Storage

Circuit Diagnosis

  - 

Circuit Diagnosis

Dave Rants

  - 

Stiff Wires from China

Experimenter's Corner

  - 

X100 Scope Probe

Good Idea done Badly

  - 

Bad Throw Rug

New Products

  - 

New Products

What the World needs Now

  - 

Large Outdoor Thermometer

Wily Widget, the Lone Inventor

  - 

Earth Battery

 

Issue 11 July 2010

Back of the Envelope Calculations

  - 

Lifted Weight Energy Storage

Circuit Diagnosis

  - 

Cracked Solder Joints

Dave Rants

  - 

Dave's Pet Peeves

Experimenter's Corner

  - 

Earth Signals

Good Idea done Badly

  - 

Bad Rubber Mulch

What the World needs Now

  - 

External USB linked HD UPS

Wily Widget, the Lone Inventor

  - 

Medical Fluid Detector

 

Issue 12 Oct 2010

Circuit Diagnosis

  - 

Wrong Capacitor Selection

Experimenter's Corner

  - 

Low Power AM Transmitter

Good Idea done Badly

  - 

Solar Powered Car Vent

New Products, 2010

  - 

New Products, 2010

What the World needs Now

  - 

Hot Car Cooler

Wily Widget, the Lone Inventor

  - 

Musical Chairs

 

Issue 13 Nov 2010

Circuit Diagnosis

  - 

Conductive Adhesive Tape Problems

Experimenter's Corner

  - 

Flameless LED Candle Power Boost

Good Idea done Badly

  - 

Bad Carriage Bolts

What the World needs Now

  - 

Switch with Hysteresis

Wily Widget, the Lone Inventor

  - 

Restaurant Table Service Request Flasher

 

Issue 14 Dec 2010

Back of the Envelope Calculations

  - 

Charge Pump Paradox

Circuit Diagnosis

  - 

Temperature Sensitive MOSFET

Experimenter's Corner

  - 

High Voltage Ceramic Capacitors for Line Powered LEDs

Good Idea done Badly

  - 

Bad 40W Fluorescent Lamps

What the World needs Now

  - 

Bovine Calving Alarm

Wily Widget, the Lone Inventor

  - 

Water Well Pump Motor Indicator

 

Issue 15 Jan 2011

Back of the Envelope Calculations

  - 

Solar Energy Myth Busting I

Circuit Diagnosis

  - 

Reversed Battery Polarity

Experimenter's Corner

  - 

Optical Fiber Pressure & Motion Test Circuit

Good Idea done Badly

  - 

Bad AC to DC Wall Power Adapters

New Products, 2010

  - 

New Products, 2010

What the World needs Now

  - 

Miniature AC to DC Power Supply

Wily Widget, the Lone Inventor

  - 

Underground Gate Opener

 

Issue 16 Feb 2011

Back of the Envelope Calculations

  - 

Space Mirror for City Illumination

Circuit Diagnosis

  - 

Modulated Light Interference

Experimenter's Corner

  - 

Ultra Low Current Circuit Examples

Good Idea done Badly

  - 

Bark Off Ultrasonic Barking Dog Deterrent Device

New Products, 2010

  - 

New Products, 2010

What the World needs Now

  - 

Space Helmet for Yard Work

Wily Widget, the Lone Inventor

  - 

Buddhist Temple Statue Light

 

Issue 17 Mar 2011

Back of the Envelope Calculations

  - 

Off-Grid Home with Electric Car

Circuit Diagnosis

  - 

Schottky Diode Leakage Current

Experimenter's Corner

  - 

Improved Solar Powered Path Light

Good Idea done Badly

  - 

Bad LED Path Light II

New Products, 2010

  - 

New Products, 2010

What the World needs Now

  - 

Emergency Electrical Power System

Wily Widget, the Lone Inventor

  - 

Battery Charging Generator Starter

 

Issue 18 May 2011

Back of the Envelope Calculations

  - 

Solar Powered Laptop Computer

Circuit Diagnosis

  - 

CFL Lamps with Day Night Switch

Experimenter's Corner

  - 

Solar Alkaline Battery Charger

Good Idea done Badly

  - 

Bad Chinese Steel Products

What the World needs Now

  - 

Garage Door Closer

Wily Widget, the Lone Inventor

  - 

Hidden Panic Switch

 

Issue 19 Aug 2011

Back of the Envelope Calculations

  - 

Portable Solar Power System for Fence Installers

Circuit Diagnosis

  - 

Gapped Ferrite Pot Core Inductor

Experimenter's Corner

  - 

Human Walk Energy Harvesting Generator

Good Idea done Badly

  - 

Bad Floor Sweeper

What the World needs Now

  - 

AC to DC Power Supply with 40KV Isolation

Wily Widget, the Lone Inventor

  - 

Soap Dispenser Monitor

 

Issue 20 Nov 2011

Back of the Envelope Calculations

  - 

Long Range Laser Communications

Circuit Diagnosis

  - 

Super Hot Ferrite Transformer

Experimenter's Corner

  - 

Tiny Solar Panels Using Photodiodes

Good Idea done Badly

  - 

Bad Magic Mesh Screen

What the World needs Now

  - 

Broadband Antennas for Metal Shops

Wily Widget, the Lone Inventor

  - 

Touch Activated Battery Powered Latching Relay

 

1st Q 2012

Back of the Envelopes Calculations

  - 

Water Train

Circuit Diagnosis

  - 

Power Supply Problems - Excessive +5v Supply Current Drain

Experimenter's Corner

  - 

Testing LED Light Intensity

Good Idea done Badly

  - 

Bad Alkaline Battery Charger

What the World needs Now

  - 

Old style Wind Mill for Electricity Generation

Wily Widget, the Lone inventor

  - 

Shooting Range Flasher

 

2nd Q 2012

Circuit Diagnosis

  - 

15 Minute Timer Does Not Time Out

Experimenter's Corner

  - 

AC Current Test Source

Good Idea gone Badly

  - 

Bad Chinese Lag Screws

What the World needs Now

  - 

Big Dial Wind Speed Indicator

Wily Widget, the Lone Inventor

  - 

Illuminated Banister

 

3rd Q 2012 

Circuit Diagnosis

  - 

Swapped Parts

Experimenter's Corner

  - 

25 Watt-hour Battery Pack for Charging Devices through USB Port

Good Idea done Badly

  - 

Bad Bug Zapper

What the World needs Now

  - 

Water Heater Flame Detector

Wily Widget, the Lone Inventor

  - 

Single Lead-Acid Cell Voltage Monitor

 

4th Q 2012

Circuit Diagnosis

  - 

Inferior 50 Ohm Power Load Resistor

Experimenter's Corner

  - 

Home Made Current Transformers

Good Idea done Badly

  - 

Pirated Audio Books

What the World needs Now

  - 

An Anti-Theft Hanging Basket Alarm

 

How did you like DC Magazine?  Should we bring it back?
 Your comments are welcomed


 

 


Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |   
Privacy Policy


Discovercircuits.com endeavors to credit original designers.   Please alert us by eMail so we can
delete links to material that have been copied without your permission
.   Thank you.


Copyright of all original material on this website is the property
of David A. Johnson, P.E. (Dave Johnson & Associates ) unless otherwise noted.  

Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.
All material is provided "as is" without guarantees or warranty of any kind, either expressed or implied.