Multimeter Resistance Test

1. Set the multimeter to read "resistance." Check that the two probes are inserted in the right holes.
2. What does the readout say when the probes are not touching anything? When the two probes are separated, there is an infinite resistance separating them, since air does not conduct electricity. Make a mental note of your multimeter's readout for infinite resistance, because it varies with the manufacturer.
3. Touch the two probes together. Now what does the readout say? When you touch the two probes together, the resistance is close to zero, since the metal tips are excellent conductors.
4. Measure the resistance of some resistors that are not attached to a circuit. For example, test resistors of 100 Ω (ohms), 10,000 Ω, and 1 MΩ (megaohm, or 1 million ohms). You can buy these online at www.radioshack.com. Touch the probes to the wires on either side of the central cylinder. Watch the units: a "k" means kilo-ohms (thousands of ohms), and an "M" means megaohms. Look online for a chart that tells you how to read the value of the resistance based on the colored bands.
5. Never measure resistance in a circuit when power is applied. You must also discharge capacitors in a circuit before measuring resistance, because if there is any source of current other than the multimeter itself, you will get erroneous readings. If the circuit you are working with has large capacitors, you should test them to see if they are carrying a charge. Test the capacitor for charge using a voltmeter, set to high DC voltage. If there is a charge on the capacitor, use a high-wattage resistor to discharge it. Carefully touch the two leads of the resistor to the leads of the capacitor. It may take several seconds for the capacitor to discharge. For more details about how to safely discharge capacitors, visit the following website: Capacitor Testing, Safe Discharging, and Other Related Information

Liquid Crystal Display (LCD)

                                          Short for liquid crystal display, a type of display used in digital watches and many portable computers. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

Monochrome LCD images usually appear as blue or dark gray images on top of a grayish-white background. Color LCD displays use two basic techniques for producing color: Passive matrix is the less expensive of the two technologies. The other technology, called thin film transistor (TFT) or active-matrix, produces color images that are as sharp as traditional CRT displays, but the technology is expensive. Recent passive-matrix displays using new CSTN and DSTN technologies produce sharp colors rivaling active-matrix displays.

Most LCD screens used in notebook computers are backlit, or transmissive, to make them easier to read.

A color television picture tube contains three electron guns, one corresponding to each of the three primary colors of light—red, green, and blue. Electromagnets direct the beams of electrons emerging from these guns to continuously scan the screen. As the electrons strike red, green, and blue phosphor dots on the screen, they make the dots glow. A screen with holes in it, called a shadowmask, ensures that each electron beam only strikes phosphor dots of its corresponding color. The glow of all the dots together forms the television picture.

Difference between microprocessor and microcontroller

Basic block diagram of Microcontroller

Microprocesser

                                                                                                                             T                                         The microprocessor is the integration of a number of useful functions into a single IC package other wise it can be call it as a CPU.At the same time  a microcontroller is obtained by integrating the key components of microprocessor,RAM, ROM, and Digital I/O . Microcontrollers are usually designed to perform a small set of specific functions for example as in the case of a Digital Signal Processor which performs a small set of signal processing functions and it is  widely used to regulate the brakes on all four wheels, or to regulate the car air conditioning .But Microprocesser  performs a wide range of task ie microprocessor in a PC.The basic difference between the microprocessor and Microcontroller is that we can interface a microcontroller directly means "for example we can directly connect a keyboard to microcontroller to any of its ports"....where as for microprocessor we can't interface directly...we require a circuit board since it requires ram,ic's.....etc.,!We can directly interface digital and analog signal for processing.  But it is not the case in the microprocessor.Microprocessor is the device  that does not have memory(internal),in micontroller it has internal memory and has connected directly to pheripheral device.Microcontroller differs from a microprocessor in many ways. First and the most important is its functionality. In order for a microprocessor to be used, other components such as memory, or components for receiving and sending data must be added to it. In short that means that microprocessor is the very heart of the computer. On the other hand, microcontroller is designed to be all of that in one. No other external components are needed for its application because all necessary peripherals are already built into it.
Microprocesser can be control Multiple Application.
eg. System Design.

Microcontroller can be control Single or Particular Application Only.

eg. embedded systems.

Another way of considering this is:

If you want to run a video game you probably need a microprocessor.
If you want to run a microwave oven you probably need a microcontroller.