During 6th grade science we had a chapter on Last time we learned that under patent law the machine.Would you expect a modern electronic memory stick to be a machine? Probably not. But, under patent law it is. It’s an electronic device, and as such it’s made up of multiple parts, including integrated circuit chips, resistors, diodes, and capacitors, all of which are soldered to a printed circuit board where they interact with one another. They do so electrically, through changing current flow, rather than through physical movement of parts as in our diesel engine. A transformer is an example of another type of machine. An electrical machine. Its fixed parts, including wire coils and steel cores, interact dynamically both electrically and magnetically in order to change voltage and current flow. Electromechanical, the most complex of all machine types, includes the kitchen appliances in your home. They consist of both fixed and moving parts, along with all the dynamic interactions of mechanical, electronic, and electrical machines. Next time we’ll continue our discussion on the second hurtle presented by 35 USC § 101, where we’ll discuss what is meant by ___________________________________________ |

## Posts Tagged ‘voltage’

### Determining Patent Eligibility – Part 4, Machines of a Different Kind

Sunday, April 28th, 2013### Transistors – Voltage Regulation Part XIII

Monday, October 15th, 2012
Last time we learned how the Zener diode, an excellent negotiator of current, is involved in a constant trade off, exchanging current for voltage so as to maintain a constant voltage. It draws as much current through it as is required to maintain a consistent voltage value across its leads, essentially acting as voltage regulator in order to protect sensitive electronic components from power fluctuations. Now let’s revisit our example power supply circuit and see how Ohm’s Law is used to determine the amount of electric current, ## Figure 1
If you’ll recall, Ohm’s Law states that current flowing through a resistor is equal to the voltage across the resistor divided by its electrical resistance. In our example that would be R. In fact, the voltage across _{Limiting}R is the difference between the voltages at each of its ends._{Limiting} Applying this knowledge to our circuit, the voltage on one end is V. According to Ohm’s Law the equation which allows us to solve for _{Zener}I is written as:_{PS}
V – _{Unregulated}V) ÷ _{Zener}R_{Limiting} And if we have a situation where V, such as when the voltage of an unregulated power supply like a battery equals the Zener voltage of a Zener diode, then the equation becomes:_{Zener }( V) = 0_{Zener }And if this is true, then the following is also true:
R= 0_{Limiting} In other words, this equation tells us that if V, then the current _{Zener}I will cease to flow from_{PS} the unregulated portion of the circuit towards the Zener diode and the external supply circuit. Put another way, in order for I to flow and the circuit to work, _{PS}V must be greater than _{Unregulated}V._{Zener} Next week we’ll continue our discussion and see why the resistor ____________________________________________ |

### Transistors – Voltage Regulation Part X

Monday, September 24th, 2012 Through the ages it’s been common practice to name important discoveries after those who discovered them. For example, James Watt was a mechanical engineer who improved the steam engine by finding a solution to the problem of steam condensing into water inside the engine, a phenomenon which resulted in the engine cooling and reducing its efficiency. Thus it was fitting that a metric unit of power, the was named in his honor. Today we’ll become acquainted with the man behind the naming of the watt,Clarence Zener,Zener diode, and take a look at his contributions with regard to the function of this electrical component.
Last time we began our discussion on electrical components known as ## Figure 1
Electric current flows through the Zener Diode just as it does through a standard diode. But when the current flows in reverse, that’s where the similarity ends. See Figure 2. ## Figure 2
When current tries to flow in the reverse direction, the Zener diode acts as an electrical conductor and allows current to pass through it. In other words, it doesn’t block current flow as standard diodes do. At this point, you may be asking, “What’s so special about that?” Perhaps you’ve made the connection that it behaves no differently than a metal wire. But that isn’t entirely correct. You see, when current passes in the reverse direction through the Zener diode, it maintains a constant voltage. This is called the The significance here is that within the circuit, any electronic component connected across the leads of a Zener diode will be supplied with a constant, unchanging voltage. Thus the Zener diode works as a voltage regulator, enabling devices connected to it to have smooth, uninterrupted operation at a constant voltage. It should be noted that this phenomenon only happens when the current flowing through the Zener diode is flowing in reverse.V_{Zener}.Next time we’ll look at a basic regulated power supply circuit to see how a Zener diode is incorporated in order to maintain a consistent output voltage. ____________________________________________ |

### Transistors – Voltage Regulation Part VII

Monday, September 3rd, 2012 Back when television had barely escaped the confines of black and white transmission there was a men’s clothing store commercial whose slogan still sticks in my mind, “Large and small, we fit them all.” It’s a nice concept, but unfortunately the same doesn’t always apply to electronic power supplies.
Last time we learned that when the electrical resistance changes on an unregulated power supply its output voltage changes proportionately. This makes it unsuitable for powering devices like microprocessor chips, which require an unchanging voltage to operate properly. Now let’s look at another shortcoming of unregulated power supplies, that being how one supply can’t fit both large and small voltage requirements. Figure 1 shows the components of a simple unregulated power supply. ## Figure 1
The diagram illustrates the voltage changes taking place as electric current passes through the supply’s four components, which ultimately results in the conversion of 120 volts alternating current (VAC) into 12 volts direct current (VDC). First the transformer converts the 120 VAC from the wall outlet to the 12 volts required by most electronic devices. These voltages are shown at Points A and B. The voltage being put out by the transformer results in waves of energy which alternate between a positive maximum value, then to zero, and finally to a maximum negative value. But we want our power supply to produce 12 VDC. By VDC, I mean voltage that never falls to zero and stays at a positive 12 volts direct current consistently. This is when the diode bridge and capacitor come into play. The diode bridge consists of four electronic components, the diodes, which are connected together to form a bridge and uses semiconductor technology to transform negative voltage from the transformer into positive. The result is a series of 12 volt peaks as shown at Point C. But we still have the problem of zero voltage gaps between each peak. You see, over time the voltage at Point C of Figure 1 keeps fluctuating between 0 volts and positive 12 volts, and this is not suitable to power most electronics, which require a steady VDC current. We can get around this problem by feeding voltage from the diode bridge into the capacitor. When we do that, we eliminate the zero voltage gaps between the peaks. This happens when the capacitor charges up with electrical energy as the voltage from the diode bridge nears the top of a peak. Then, as voltage begins its dive back to zero the capacitor discharges its electrical energy to fill in the gaps between peaks. In other words it acts as a kind of reserve battery. The result is the rippled voltage pattern observed at Point D. With the current gaps filled in, the voltage is now a steady VDC. The output voltage of the unregulated power supply is totally dependant on the design of the transformer, which in this case is designed to convert 120 volts into 12 volts. This limits the power supply’s usefulness because it can only supply one output voltage, that being 12 VDC. This voltage may be insufficient for some electronics, like those often found in microprocessor controlled devices where voltages can range between 1.5 and 24 volts. Next time we’ll illustrate this limitation by revisiting our microprocessor control circuit example and trying to fit this unregulated power supply into it. ____________________________________________ |

### Transistors – Voltage Regulation Part VI

Sunday, August 26th, 2012 Believe it or not as a kid in grade school I used to hate math, particularly algebra. None of my teachers were able to decipher its complexities and render it comprehensible to me or the majority of my classmates. Then in high school everything changed. I had Mr. Coleman for freshman algebra, and he had a way of making it both understandable and fun, in a challenging kind of way. With 40 years of teaching under his belt, Mr. Coleman knew exactly how to convey the required information in an understandable manner, and to this day I find his insights useful in solving engineering calculations.
Last time we began our discussion on Ohm’s Law and how it may be applied to our example circuit to solve for the electrical current flowing through it. Let’s continue our discussion to see how the Law applies to only one part of the circuit. Then, we’ll use a little algebra to show how the output voltage of an unregulated power supply is affected by changes in ## Figure 1
To help us see things more clearly, in Figure 1 we’ll cover up the inside workings of the unregulated power supply side of the circuit and concentrate on the external supply part of the circuit alone. Since Ris the same as the power supply output voltage, _{Total }V._{Output} In my previous article, we learned that according to Ohm’s Law, the current flowing through a resistance is equal to the voltage applied to it, divided by the resistance. The fact that I, flowing through :_{ }R_{Total}
Now let’s pull the cover off of the unregulated power supply again to see what’s going on within the circuit as a whole. ## Figure 2
In Figure 2 we can see that the current,
We can combine the above two equations for R, _{Internal}R, and _{Total}V:_{DC}
Then, by rearranging terms and applying the cross multiplication principle of algebra we can solve for R_{Total:}
This equation tells us that although V will fluctuate when _{Output}R does. This fact is demonstrated in our equation when we make use of algebra. That is to say, when a term changes on one side of the equation, it causes the other side of the equation to change as well. In this case, when _{Total}R changes, it causes _{Total}V to change in proportion to the fixed values of _{Output}V and _{DC}R._{Internal}Next time we’ll look at another shortcoming of unregulated power supplies, more specifically, how one supply can’t power multiple electrical circuits comprised of different voltages. ____________________________________________ |

### Transistors – Voltage Regulation Part V

Sunday, August 19th, 2012 I’m sure you’ve seen the television commercials warning about harmful interactions between prescription medications. By the same token electronic circuitry can also be adversely affected by certain combinations of electrical components, as we’ll discuss in today’s blog.
Last time we R increases, the electrical current, _{Total}I, decreases, and when R decreases, _{Total}I increases. In contrast to this increasing/decreasing activity of the total resistance Rdoesn’t fluctuate. Let’s explore Ohm’s Law further to see how the static effect of _{Internal}, Rcombines with the changing resistance present in _{Internal }R to adversely affect the unregulated power supply output voltage, _{Total}V, causing it to fluctuate._{Output}## Figure 1
In Figure 1 R are operating in series, meaning they are connected together like sausage links. In this configuration their two resistances add together as if they were one larger resistor. _{Internal} Generally speaking, Ohm’s Law sets out that the current,
In the case of the circuit represented in Figure 1, the resistors R are connected in series within the circuit, so their resistances must be added together to arrive at a total power demand. Voltage is applied to these two resistors by the same voltage source, _{Total}V. So, for the circuit as a whole Ohm’s Law would be written as:_{DC}
But, Ohm’s Law can also be applied to individual parts within the circuit, just as it can be applied to a single kitchen appliance being operated on a circuit shared with other appliances. Let’s see how this applies to our example circuit’s ____________________________________________ |

### Transistors – Voltage Regulation Part IV

Sunday, August 12th, 2012 We’ve all popped a circuit breaker sometime in our lives, often the result of making too heavy of an electrical demand in a single area of the house to which that circuit is dedicated. Like when you’re making dinner and operating the microwave, toaster, mixer, blender, food processor, and television simultaneously. The demand for current on a single circuit can be taxed to the max, causing it to pop the circuit breaker and requiring that trip to the electrical box to flip the switch back on.
Last time we began our discussion on unregulated power supplies and how they’re affected by power demands within their circuits. Our schematic shows there are two basic aspects to the circuit, namely, its direct current source, or R. Now let’s connect the power supply output terminals to an external supply circuit through which electrical current will be provided to peripheral devices, much like all the kitchen gadgets mentioned above._{Internal}## Figure 1
The external supply circuit shown in Figure 1 contains various electronic components, including electric relays, lights, and buzzers, and each of these has its own internal resistance. Combined, their total resistance is Current, notated as
I can change, that is, increase or decrease, depending on how many components the microprocessor has turned on or off within the external supply circuit at any given time. When R increases, electrical current, _{Total}I, decreases. When R decreases, electrical current _{Total}I increases. Next time we’ll continue our discussion on Ohm’s Law, introduced last week, to show how the static effect of R to_{Total} adversely affect an unregulated power supply’s output voltage.____________________________________________ |

### Transistors – Voltage Regulation Part II

Sunday, July 29th, 2012 I joined the Boy Scouts of America as a high schooler, mainly so I could participate in their Explorer Scout program and learn about electronics. I will forever be grateful to the Western Electric engineers who volunteered their personal time to stay after work and help me and my fellow Scouts build electronic projects. The neatest part of the whole experience was when I built my first regulated power supply with their assistance inside their lab. But in order to appreciate the beauty of a regulated power supply we must first understand the shortcomings of an unregulated one, which we’ll begin to do here.
Last time we began to discuss how the output voltage of an unregulated power supply can vary in response to power demand, just as when sprinklers don’t have sufficient water flow to cover a section of lawn. Let’s explore this concept further. ## Figure 1
Figure 1 shows a very basic representation of a microprocessor control system that operates three components, an electric relay (shown in the blue box), buzzer, and light. These three components have a certain degree of internal electrical resistance, annotated as R, and _{B}R respectively. This is because they are made of materials with inherent imperfections which tend to resist the flow of electric current. Imperfections such as these are unavoidable in any electronic device made by humans, due to impurities within metals and irregularities in molecular structure. When the three components are activated by the microprocessor chip via field effect transistors, denoted as FET 1, 2 and 3 in the diagram, their resistances are connected to the supply circuit._{L} In other words, R, and _{B}R create a combined level of resistance in the supply circuit by their connectivity to it. If a single component were to be removed from the circuit, its internal resistance would also be removed, resulting in a commensurate decrease in total resistance. The greater the total resistance, the more restriction there is to current flow, denoted as _{L}I. The greater the resistance, the more I is caused to decrease. In contrast, if there is less total resistance, I increases. The result of changing current flow resistance is that it causes the unregulated power supply output voltage to change. This is all due to an interesting phenomenon known as
where, Next time we’ll apply Ohm’s Law to a simplified unregulated power supply circuit schematic. In so doing we’ll discover the mathematical explanation to the change in current flow and accompanying change in power supply output voltage we’ve been discussing. ____________________________________________ |