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Issue 14,  December  2010- Page 1                                                                                                   Previous Issues     
  

Let's drop in on Wily and look over his shoulder at his latest project....

Water Well Pump Motor Indicator

One of Wilyís neighbors stopped by and described a problem he was having with his water well pump.  The guy needed Wilyís help.  He wanted a simple way to know when the submersible pump motor was turned on and running, so the neighbor could do some troubleshooting.  The water well head and electrical connections were located some distance from the back of the neighborís house, inside a small shed.  What the neighbor wanted to do was turn on a small light whenever the pump turned on. 

He wanted the light to be bright enough so it would be visible from the house.  He was not sure, but the neighbor thought that the pump motor was turned on and off by switches deep down the well.  Therefore, there was not a simple switched voltage to tap into at ground level in the shed. How could he turn on a light when the pump was running?  Wily thought about it for a few seconds and then told the neighbor that he thought he had a solution.....

con't page 7

Wily Widget,
the Lone Inventor
 with Gadget & Gizmo

WHAT THE WORLD NEEDS NOW is a....Bovine Calving Alarm
This request came to me by way of a dairy farmer in Minnesota.  He has a large number of milk cows and breeds them.  He said he lost a few cows because they had trouble giving birth in the middle of the night.  What could be done to help him? ....
story con't on page 6

Title
By: Dave Johnson  
                      
coming soon ....

  story con't on page 8

New Products 2009
New product announcements are made nearly every day.  I subscribe to many trade journals and each is filled with hundreds of flashy advertisements.  But, only a few of those product ads catch my eye.  Since Iím a circuit designer, I especially like those components that trigger many new application ideas in my mind.  Sometimes it is the smallest products that are the most useful.  I often discovered new products in surplus electronic catalogs.  The surplus companies often buy up stock that came from companies that went out of business.  Bad marketing or bad management may have killed a perfectly good product idea.  Their loss can be your gain if you can spot the bargain.                               
High Voltage Ceramic Capacitors for Line Powered LEDs
By: David Johnson
                                                                                                            
Many AC line powered DC supplies for LEDs wired in long series strings use a series connected capacitor to limit the current drawn from the power line.  Typically, these capacitors are Mylar or polyester film devices.  However, I think that much smaller ceramic type capacitors might also work.  Below is a photo showing a pair of capacitors each with the same 0.47uF 250v rating.  Clearly the ceramic device is much smaller.....

   story con't on page 4

Temperature Sensitive MOSFET     

A while back I was asked by a company to look into why one of their products failed to operate properly in cold temperatures.  A simplified version of the circuit is shown below. Two n-channel MOSFETs and a few resistors are wired to form a flip/flop latch circuit.  Each time the pushbutton switch is pressed, ......

 story con't on page 3

Bad 40W Fluorescent Lamps
Is it just me, or are standard 48 inch 40W florescent lamps dying much faster these days?  I remember when these things would last 3 years or more.  Now, Iím replacing them more like every 6 months.  Some donít even last one month.  When I moved into my current house some 12 years ago, I installed a number of fluorescent lamp fixtures on the ceiling of the garage.  The fixtures hold two standard 40 watt, 48 inch cool white lamps.....


story con't on page 5    

Charge Pump Paradox
 

Below is a pretty simple circuit.  At first blush it seems fairly logical.  It was conceived by a Discover Circuits visitor.  He thought the circuit would allow the low voltage from a single solar cell to charge a large super capacitor to a much higher voltage using a charge pump method.  But, would this circuit work?....

story con't on page 2 


December  2010     Issue 14

Page 1 Back
Envelope
Circuit
Diagnosis
Experimenter's
Corner
Good Idea
gone Badly
New Products Rants &
Raves
What the World
needs Now
Wily Widget


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