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Showing posts from May, 2013

### Opinions or Onions: The Convention of Academic Presentation

Because both may make you cry, but when cooked and digested, are delicious and nutritious.

I always get extremely vexed when a lot of textbooks and lectures introduce concepts for the first time so formally that they end up as mere functions to the listener, (maybe an attempt to make the science appear like a very difficult subject matter or a faithful following of convention), so much so that the soul or true usefulness of the concept is lost. Take for example a lecture in industrial electronics. The students become familiar with the industrial electronic components such as the SCRs, UJTs, thyristors, diacs, triacs, you name it. And, of course, they'll learn how they function as manipulators of power delivery and how to design the triggering circuits and resistors (like for the misleadingly named Programmable Unijunction Transistor or PUT). Fast forward a couple years to the future when they are now working in the industry. Say, that there is a series of loads supplied…

### Flip-Flops Unraveled

No, these flip-flops aren't the ones you wear on the beach. These flip-flops are sequential circuits (circuits whose outputs are dependent on the previous values, like a sequence - hence the name). They're made up of combinational circuits strategically pieced together so that as long as there is a power supply, their outputs follow a sequence based on past inputs. Why would we need such a circuit? Why can't we just directly feed the values we desire by using the combinational circuits that we know? Well, there are instances that we don't want immediately fed values to affect the overall output.

Take for example a security system. There are pressure transducers randomly placed all over the floor of a vault. When pressure is applied on the floor, like the weight of an adult, a voltage results and that voltage triggers a red light at a remote security facility. Now, let us say George Clooney and Brad Pitt manages to get inside the vault. While they walk acros…

### Basic Statistics Unraveled

Measures of Central Tendency

You are gathering information on the number of customers you entertain everyday in a fast food chain. You decide to sample for a period of 1 week, and you decide to assume that the number of customers you get daily is completely uncorrelated with time. You're census yields the results below:

Sunday - 1430

Monday - 950

Tuesday - 870

Wednesday - 1100

Thursday - 950

Friday - 950

Saturday - 1600

Now, you want to process the data so that you arrive with a singular value that can best represent the entirety of the data. The best and simplest processes to use are called measures of central tendency, and the 3 mostly used are the mean, median and mode.

The mean is simply the average of the data. The median is the center of the data set regardless of the value of the data. The mode is the data that has possesses the highest number of occurences.

To get the mean, simply sum the entire data set and divide by the number of data elements. (14…

### Fast Fact: Root Mean Squared Unraveled

RMS or Root Mean Squared is defined as the Root of the Mean of the Square of each sampled value of a signal (for discrete values) or the Root of the Definite Integral of the Square of each bounded function (for continuous values). But what exactly does it mean? It is actually like a means of central tendency (I use the word "like" because it doesn't exactly function the same way as an average) only that negative integers are treated as positive values by squaring them in the first place. After squaring, you take the "mean" then take the square root again to reverse the effects of squaring. Thus, the entire signal is sufficiently represented by one constant value. This constant value can be taken as DC (direct current) since DC is a constant unchanging voltage. Hence, when we take an RMS measurement of an AC signal, we are actually getting an equivalent DC signal that can replace that AC signal in terms of power delivery.

But why not use Cube-Root Mean Cube…

### Some Common Mobile Electronic Devices Usage and Maintenance Unraveled

The Cellphone

A cellular phone is basically composed of solid-state electronics. It can suffer less damage when dropped compared to a laptop under operation assuming they both experience the same amount of force when they hit the ground. It also gets damaged when soaked with water (specially saltwater, being conductive) wherein shorts can occur. Ionized water can also harm electronic components in your cellphone sensitive to static charge. I've heard of water-resistant phones, yet its still safe to take extra measures because you'll never know if there is a fault in the insulation. Its life expectancy greatly decreases when operated at higher temperatures, so exposing the mobile unit to high temperatures is a no-no. When the LCD breaks, the phone is as good as scrap unless you solder a new one on. As for viruses, the smarter the phone, the more vulnerable. Why? Because smarter phones acquire data in more ways, and the more the ways available - the higher are the chances o…