Electronics Engineering

Semiconductors are called that due to their elemental makeup, not because current is or is not flowing through them. Basically, semiconductors have a "good" number of electrons in their outer ring (valence electrons), making them (as my chemistry professor said...) "fat and happy" as they are.

Silicon is an example. It has 4 valence electrons, so it is happy. Elements in the third row of the periodic table want to have 0 (actually 8 in row 2), 4, or 8 valence electrons, and will try to steal or give away electrons to get there. This "stealing" or "giving away" causes elements to group together into molecules, but it also can cause an electrical charge build up if you can get enough atoms of one element that want electrons or want to give away electrons in a specific area.

This is why semiconductors are so important for modern circuits. Since they're "fat and happy", they don't influence whatever the designer is trying to build; they act as an unbiased base to build on.

To create electrical circuits, silicon is used as the foundation, and specific locations of the silicon disk have elements with (usually) 3 or 5 valence electrons placed onto it (called "doping"). This creates electrical potentials across the silicon; when put together in specific ways, this forms diodes, transistors, micro capacitors, exc.

For simple resistance measurements it usually doesn't matter.

Fourier series is the sum of sinusoids representing the given function which has to be analysed whereas discrete fourier transform is a function which we get when summation is done.

A capacitor that consists of thin dielectric layers interleaved with staggered metal-film electrodes; after leads are connected to alternate projecting ends of the electrodes, the assembly is compressed and sintered to form a solid monolithic block. -From http://www.answers.com/topic/monolithic-ceramic-capacitor?cat=technology

Inrush is due to the saturation of the core of the transformer.

When the highside device closes to energize the transformer, it does not always do so right at a voltage peak. The transformer core B (magnetic field) will be 90 degrees out of phase with the applied voltage, so a peak voltage close is ideal. Once it is closed, the B will continue up and down 90 degrees out of phase with the voltage. Assuming there is no residual magnetic field (B starts at zero), it will be offset by the initial non - peak close. This offset in magnetic field will cause the core to go into saturation; depending on the core design it may be further or less into saturation on different transformers.

When the core saturates, large currents flow, and these currents (normally) have a high 2nd harmonic component which is used in protective relaying to restrain for inrush.

No, even though these are parallel circuits, the voltage drop across each device is not the same in house hold circuits, or anywhere, for that matter. Different devices pull different currents. A toaster, for instance, pulls many times what a light bulb pulls. Since wires do not have truly zero resistance, those differing currents result in different voltage drops across the wires that lead to the devices. That small voltage drop in the wires results in a different voltage drop across each device, even though the device/wire is connected to the same voltage source.

A: If you have a ramp generator or make one LM555 then feed it to the zener don' t forget the limiting resistor with the scope across the zener the display will dhow its voltage and current characteristics. you can do the same for a diode even a transistor and more.

The difference between a series and parallel circuit is that a series circuit is connected in such a way that the same current intensity flows through the elements while a parallel circuit is connected in such a way that the same potential appears across their terminals.

20 milliseconds

For IT seminar, the topics could be:

Cloud computing

Android

Ethical hacking

or on any new technology .

its function is a voltage divider

The digital signals is not converted BACK to analog! it is transmitted in digital form and the receiver is converting it back to analog to drive the speakers. The signal from the microphone is converted from analog to digital with an A/D converter chip, digital signals consist of pulses of different lengths that is switching the transmitter on and off in about the same way as the old Morse code transmissions but at a much higher rate (millions of times higher)

Using Ohms Law, the answer is 120/0.5 = 240 Ohms.

It's possible there may be some company producing a magnetic product they call "flip flops" and/or flip flop sandals that are magnetic, either miniature or full, wearable sized; but, no, flip flops are not magnets, generally speaking. Flip flops are a simple type of sandal.

ans. 3 nand gates

resoon :-

OR GATE :- x+y

NAND GATE :- x'+y'

LOGIC :-so the logic is is we apply NAND to the inputs x' and y' instead of xand y we would get x+y

DESIGN PROCEDURE

1. for inverting the input x and y can be done by NAND gates ,

2. take a NAND gate and pass both x in both the inputs it means x NAND x gives you x'

3. follow similar procedure for inverting y

4. and then all the outputs of those NAND gates as the inputs of another NAND gate

yes

you could write the manufacturer for a datasheet. many send them out free.

yes, capacitive reactance is inversely proportional to frequency.

The power on switch

The space wave is the wave that propagates directly through free space, rather than via some other object or medium like the ground.

Good conductors like metals, the ionosphere, etc.

A signal jammer or jamming transmitter is a small, low-powered transmitter that interfers with receivers in an area around the jammer. The radius of the area will depend on the power of the jammer. The jammer signal will be "seen" by the receiver and it won't then be able to "see" the little signal of the remotely located transmitter that it is trying to "look at" before you turn on your jammer. The jammer transmits a signal (without modulation - it's just the carrier wave) that radiates from the jammer pretty much in all directions (for an omni-directional antenna - which is what is usually on them). This small signal reaches all receivers within the area of its effective range and "swamps" the receivers in that area. Understand that the transmitters reaching out to receivers are generally "high power" units (their power varying depending on what they're designed to do). The jammer is low power. But because the signal from the transmitter is (almost always) a long, long way away from the receivers in the jammer's area, the signal from the transmitter is very tiny in that area. The jammer, on the other hand, has a "large" signal in that area because it's so close to those receivers. It's the amount of signal that gets to a receiver that is important. If a tiny transmitter (a jammer) is "right on top" of a receiver, it will "hit" that receiver hard compared to the tiny signal getting to that receiver from the (high powered) transmitter many miles away. The general rule for power for a transmitter getting to a receiver is that the signal strength is going to be the inverse sqare of the distance from that transmitter. That means that if you have "x" amount of signal at a given spot from a transmitter and them double your distance from the transmitter, the signal will be 1/d2 or 1/22 or 1/4th the amount you had before. Double the distance again and you're down to 1/16th the original amount of signal. A little transmitter works well to jam a receiver if it's right on top of it. It will "blind" the receiver to the "real" signal from the transmitter it is trying to capture. Jammers are generally a no-no, both ethically and legally. Use your head here and think through your options if you are planning some "experimental" electronics. It is the FCC (the Feds) that get down on individuals who interfere with communications. They play hard ball. Imagine interrupting air-to-ground communications and interfering with air traffic. They'd lock you up and throw away the key. Seriously.

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