Posts Tagged ‘electrical design’

Patents, Defined

Sunday, March 31st, 2013

      While pursuing my engineering degree my professors provided me with a thorough understanding of mechanical and electrical design and instruction on how to build prototypes for testing.   As far as technical skills were concerned, I was well equipped to turn my ideas into real inventions.   Unfortunately, my engineering school, like most others, never went beyond these technical aspects of inventing.   For example, we never discussed the business and legal aspects of manufacturing and selling an invention.

      The fact is, most first time inventors have little or no understanding of how to go about obtaining a patent to prevent others from copying and profiting from their inventions.   They also tend to take a haphazard approach to inventing, neglecting important issues such as whether a market for their invention exists, or whether they will face competition already in place.   A lot of time and money can be spent developing an invention, only to discover that it had already been patented by someone else.   They do all the up-front work, blissfully unaware of the repercussions of negative possibilities, like getting sued by any existing patent holder, suits which are among the most expensive to defend.

      For most individuals the patent process is a hotbed of mysteries and misconceptions.   Let’s start unraveling them by first gaining a basic understanding of what a patent is.

      In short, a patent grants you a legal right, much like other legal rights you may be more familiar with.   For example, if you own property, say a car or piece of real estate, you’re provided with a legal document known as a title.   This title defines your legal right to own that property.

      Similar to a title, a patent grants you the legal right to own intellectual property, or IP, as its inventor.   IP is a term used in the business and legal arenas to refer to creations of the inventor’s mind.   Once patented, these creations become the property of the inventor, and they have commercial value.   This value is derived from the fact that the patent can be used to exclude others from producing the invention and profiting from it.   The IP rights can also be sold or licensed to others for a profit.

      IP can encompass subjects as diverse as machinery, articles of manufacture, compositions of matter, and many diverse processes, all of which we’ll look into during the course of this blog series.


Transistors – Digital Control Interface, Part III

Sunday, July 1st, 2012
     When I was in engineering school in the mid 1970s microprocessor chips were still a fairly new concept.  Scientific calculators were the size of a brick back then, and they weighed almost as much, and there were no personal computers.

     I remember doing homework on the UNIVAC 1108 mainframe computer at school.  To program it I had to sit at a monster of a keypunching machine for which I punched an endless array of holes into paper cards.  These holes acted as the programming logic to instruct the computer what functions to perform.  The 1108 computer’s mainframe was so huge it was housed in an adjoining room the size of a house.  Since the 1980s advances in microprocessor technology have increased computing power and dramatically reduced the size of components, making things like laptops, smart phones, and sophisticated electronic products possible.

     Last time we began looking at my design solution for the control of a machine which developed medical x-ray film and made use of a microprocessor chip to automate its operation.  A field effect transistor (FET) acts as a digital control interface between its 5 volt direct current (VDC) microprocessor and a 12 VDC buzzer.  Figure 1 shows what happens when someone presses the button to put everything into action and the microprocessor starts timing. 

 microprocessor control using a MOSFET

Figure 1


     With the button depressed the chip senses 5 VDC from the power supply on its input lead.  This in turn signals the computer program to turn the product on.  The program then begins counting down the minutes, all the while maintaining a 0 voltage output from the chip’s output lead.  With no voltage present on its G lead, the FET does not permit electrical current to flow from the 12 VDC supply, through the buzzer, through D and S, and down to electrical ground.  The buzzer remains silent.

Field Effect Transistor

Figure 2


     Figure 2 shows what happens when the program begins its 40-minute warming sequence.   The chip raises the output lead voltage to 5 VDC and applies it to G, then the FET permits electric current to flow through it to ground from the 12 VDC supply and the buzzer.  Now supplied with power, the buzzer sounds.  Then, per programming instructions, after 2 seconds the program shuts off the voltage in the chip’s output lead, current is cut off, and the buzzer goes silent.

     Next time we’ll see how an FET can be used as an interface between a microprocessor and another higher powered device, that of a 120 VAC motor that’s used to move x-ray film through a series of processes within the developer.