### Electromagnets

We defined POWER as the RATE of doing work. The actual work or capacity to do work is called ENERGY . Energy can be Kinetic (dynamic), Potential (static), or Radiant (electromagnetic) in nature. Energy, according physical law of "Conservation of Energy", is never lost nor gained. It may be changed from one form to another, but it never just "disappears". Just like in our resistor, we had energy being used which was dissipated as heat. The electrical energy was transformed into heat energy. It didn't disappear, it merely changed form. There are many other forms of energy. Some other forms of energy are light, sound, momentum, and MAGNETISM .

We are all familiar with magnets, and their peculiar properties which make them seem almost magical. A magnet can be used to hold a screw onto a screwdriver, to lift a car, or find your way in the forest. But what is it that makes a magnet do what it does?

If we take a magnet, and mark one end of it, we can identify one end from the other. If we then suspend the magnet from a string, so that it is free to rotate, we will notice that one end will ALWAYS point toward the north, and that it will ALWAYS be the same end of the magnet that points north.

From this, we have concluded that there is a NORTH POLE and a SOUTH POLE on every magnet. Typically the north pole is marked with an N, and south pole is marked with an S.

Now if we take two magnets with known, marked poles, and bring the North Pole of one magnet close to the South Pole of the second magnet, the two magnets will PULL TOWARD one another until they are connected. If we reverse the experiment, and bring the North Pole of one magnet, near the North Pole of the second magnet, they will PUSH AWAY from each other. This effect is called the LAW OF POLES which states:
OPPOSITE POLES ATTRACT each other, whereas LIKE POLES REPEL each other.

Why is it that magnets act this way? And why do magnets have poles? These are questions which science has found difficult to answer. It is believed, though, that according to the Molecular Theory of Magnetism inside of all magnets, the tiny molecules that the magnet are made of, are all little tiny magnets in themselves, and that they are all lined up in a row.

In a normal piece of steel, for instance, the molecules are arranged in random order, with positive and negative poles scattered about in all directions.
But when magnetized, the tiny magnetic molecules line up, allowing the whole piece of steel to act like one big magnet.

If we place a magnet beneath a piece of paper, and place iron filings on top of the piece of paper, the result would look something like the example to the right. The iron filings will arrange themselves to LOOK like the invisible magnetic force which surrounds the magnet. This invisible magnetic force which exists in the air or space around the magnet, is known as a MAGNETIC FIELD , and the lines are called MAGNETIC LINES OF FORCE .
Now if we take a non-magnetic object, such as a glass rod, and place it within the path of a magnetic field, the lines of force produced by the field would pass right through the object.

If, however, we wrap a magnetically conductive layer around the object, such as a soft iron, the iron will cause the lines of force to bend, and go around the object instead of through it. This is called a SHIELDING effect.

### Build a Low Noise And Drift Composite Amp Circuit Diagram

How to Build a Low Noise And Drift Composite Amp Circuit Diagram. This circuit offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance.
Low Noise And Drift Composite Amp Circuit Diagram

Compared to a standalone FET input operational amplifier, the composite amplifier circuit exhibits a 20-fold improvement in voltage offset and drift. In this circuit arrangement, A1 is a highspeed FET input op amp with a closed-loop gain of 100 (the source impedance was arbitrarily chosen to be 100 kfl). A2 is a Super Beta bipolar input op amp. It has good dc characteristics, biFET-level input bias current, and low noise. A2 monitors the voltage at the input of A1 and injects current to Al`s null pins. This forces A1 to have the input properties of a bipolar amplifier while maintaining its bandwidth and low-input-bias-current noise.

### High Power Output Amplifier TDA7294

The famous SGS-THOMSON ST Microelectronics has introduced a Hi-Fi DMOS high-power amplifier circuit TDA7294, its sound great taste bile, which due to its internal circuit from input to output are field-effect devices, rounded sound Mild, delicate Rounuan.  However, with its assembly amplifier, only TDA7294 single-output power is only 70 W, BTL access law is 100 W from top to bottom, do not feel that power cushion. The author several tests, used to promote TDA7294-level, direct-drive one to four pairs of high-power transistor parallel, the output of strong currents, the power output of 400 W (mono), and the circuit is simple and no need to debug that can reliably work Basically, the IC has maintained a sound and performance.  Ruzuo The figure below shows, R6 for the feedback resistor, the author of the value in debugging 22 k Î© more appropriate, R6 also decided this circuit gain, the gain value will increase.  Quiescent current depends on the power of R7, R8, when its value…

### Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram.To day if we are talking about expert Cell phone Jammers we are conversing about this schematic underneath. First off all you should be very very cautious how to use this apparatus. Its completely illegal and so the reason. I post this Circuit is only for educational and testing causes. This type of apparatus is being utilised by security for VIPS, particularly at their limousines to avoid blasting device initiating while the vehicle passes from the goal cell phone-bomb. Off course there are those who use it to make a antic or to make the persons crazy in the rectangle block you are.
The power of the jammer is currently sufficient to do your thing, but certainly you can place a 30W linear power amp at the RF output and impede a much wider locality. So, Be pleasant individual with that and recall that there are people who may need desperately to obtain or make a call and one of them could be you! And if you can't oppose of functioning …