... output of the 555 IC, which is pin 3, goes LOW. This in turn activates and lights the top LED (the HIGH indicator). Logic probes derive their operating power from the PCB under test. Care should be taken in attaching the clips to safe voltages; you may want to first use a Volt Meter (Digital Multi Meter) to verify the hook up points have good voltages. The four diodes protect the IC from reverse polarity. Capacitor C1 prevents transient voltage from affecting the logic probe when the black lead is not connected. Pin 5 of the 555 IC is grounded through resistor R1. The logic probe will indicate a HIGH for 2V or greater, and a LOW for 0.8V or less. To use this logic ...
... dawn of the antibiotic era. In less than two decades, major advancements had been made in the development of antibiotics. There were so many different antibiotics developed that doctors and scientists focused their attention on other problems plaguing the nation. Doctors prescribed antibiotics frequently, often when they were not even needed. According to a 1998 report by the Institute of Medicine, up to fifty percent of antibiotics are prescribed unnecessarily. This blatant overuse of antibiotics had a profound effect on the efficiency of the drugs in the future. The wonder drugs that had been so effective in treating an array of diseases had started to lose ...
... the octet rule, when atoms react,, they tend to do so in such a way that they attain an outer shell containing eight electrons. The factors that effect the formation of ions are ionization energy, electron affinity, lattice energy. Figure 1 The transfer of electrons involved in the formation of (a) sodium chloride and (b) calcium fluoride. Each atom forms an ion with an outer shell containing eight electrons. For many elements, compounds cannot be formed by the production of ions, since the energy released in the formation of the lattice of ions would be insufficient to overcome the energy required to form the ions would be insufficient to overcome the energy r ...
... of the atmosphere are Carbon Dioxide at 95.32%; Nitrogen at 2.7%; Argon at 1.6%; Oxygen at 0.13%; Water at 0.03%; and Neon at 0.00025 %. Martian air contains only about 1/1,000 as much water as our air, but even this small amount can condense out, forming clouds that rise high in the atmosphere or swirl around the slopes of towering volcanoes. Local patches of early morning fog can form in valleys. At the Viking Lander 2 site, a thin layer of water frost covered the ground each winter. There is evidence that in the past a denser Martian atmosphere may have allowed water to flow on the planet. Physical features closely resembling shorelines, gorges, riverb ...
... discreet touch. They make a little sound, less than the least of sounds. No bird at night in the marshes rustles so slightly, no men, though men are the most refined of living beings, put so passing a stress upon their sacred whispers or their prayers. The leaves are hardly heard, but they are heard just so much that men also, who are destined at the end to grow glorious and to die, look up and hear them falling. There is an infinite amount of qualities of describing the leaves. The color is not a mere glory: it is intricate. If you take up one leaf, then you can see the sharp edge boundaries which are stained with a deep yellow-gold and are not defined. Nor ...
... in each cell of their bodies instead of the usual number of 46. This extra sex (X) chromosome causes the distinctive make-up of these boys. All men have one X chromosome and one Y chromosome, but sometimes a variation will result in a male with an extra X. This is and is often written as 47,XXY. There are other, less common variations such as 48,XXYY; 48,XXXY; 49,XXXXY; and XY/XXY mosaic. All of these are considered variants. The major effect of the extra X chromosome in boys with seems to be the function of the testes. The testes produce the major male sex hormone testosterone and the amount of this hormone may be decreased in boys with . When these boys re ...
... brain doesn't just control your organs, but also can think and remember. That part of the brain is called the mind. PROTECTING THE BRAIN Twenty-eight bones make up the skull. Eight of these bones are interlocking plates. These plates form the cranium. The cranium provides maximum protection with minimum weight, the ideal combination. The other twenty bones make up the face, jaw and other parts of the skull. Another way the brain keeps it self safe is by keeping itself in liquid. Nearly one fifth of the blood pumped by the heart is sent to the brain. The brain then sends the blood through an intricate network of blood vessels ...
... gas vaporizes to fill the space. The valve is normal held shut by the pressure in the can, and by the coil spring directly below the valve stem. When the push button is pressed, it forces the valve stem down in its housing, uncovering a small a small hole which leads up through the stem to the nozzle in the button. This allows the product to be forced up the dip tube by the gas pressure in the can. The nozzle is shaped to give a spray or a continuous stream. To produce a fine mist, a propellant is used which mixes with the product. The two leave the nozzle together and the propellant evaporates a soon as it reaches the air, breaking the product in to tiny drop ...
... Another new area, called "virtual reality" is currently being tested. This is away to simulate reality on a monitor. In order to feel this so-called realityyou have to wear special electronic glasses and an electronic suit. Fastened tothe suit are sensors, which send information to the main computer. Thiscomputer works with the data and displays them on the electronic spectacles. This is a technique which use three-dimentional views, therefore the scenery seems incredibly realistic. If you want to be a boxer, simply change thescenery on the main computer, and you are in the ring.Today, many kids have got video games. You could say these games are thepresent's answe ...
... when shopping for home entertainment components.A final consideration that consumers should give special attention is the accessibility of the systems. In today’s growing entertainment market, the difficulty in accessing video and DVD movies can play a large part in the decision of which component is right for the consumer.METHODSThe beginning of any research project is in the decision of a topic to research. I chose to research the differences between the VCR and DVD home entertainment systems because the intricacies of the systems and the ways in which they work greatly interest me. I began my work using ordinary encyclopedias, found in the Rosewood High School ...
