## Conductors and Insulators

Because of the distribution of electrons in the VALENCE RING of an atom, some elements will allow electrical current to flow easier than others. Materials which easily allow the flow of electric current are called CONDUCTORS . CONDUCTORS do not hold tightly to the electrons in their VALENCE RING, and are said to have a large number of FREE ELECTRONS . Some examples of good conductors are Gold, Silver, Copper, Aluminum, Zinc, and Carbon. Other elements do not allow electrical current to flow easily, and these are called INSULATORS . INSULATORS tend to hold tightly to the electrons in their VALENCE RING, and do not want to share with other atoms. Some examples of good insulators are Quartz, Mica, Teflon, Polystyrene, and Water. (Yes, water is an insulator.... not a conductor. This will be explained later in more detail).

## Resistors and Resistance:

If water is moving through a hose, we say that it has FLOW .

If we restrict the flow, by pinching the hose, we are causing friction at the point of restriction. This friction can be said, is resistance to the flow of the water.

Electricity, according to Benjamin Franklin, acts like a fluid. It flows and has a measurable CURRENT . We can restrict its flow by adding electrical friction. We say that the restriction of electrical flow is called RESISTANCE and that a device which causes such RESISTANCE is called a RESISTOR . All materials, even the very best CONDUCTORS demonstrate a certain amount of RESISTANCE to electron flow.

In order to compare the resistance of various materials, we need to have some standard unit of measurement. The unit of measurement for resistance is called the Ohm , and is indicated by the Greek letter Omega ( Î© ).

One Î© is defined as the amount of resistance that a 1000 foot piece of #10 copper wire has. A 3000 foot piece of #10 copper wire would have 3 Ohms of resistance. A 500 foot piece of #10 copper wire would exhibit 1/2 an Ohm, etc. Although Ohm is the basic unit, KiloOhm and MegOhm are frequently used. 1 KiloOhm (K Î©) is equal to 1 thousand Î©. 1 MegOhm (M &Omega) is equal to 1 million Î©.

There are 4 factors that determine the resistance of a material:
(1) Type of Material
The resistance of various types of materials are different. For instance, copper is a better conductor of electricity than gold, and therefore has less resistance.
(2) Length
The resistance of a material is directly proportional to its length. The longer the material is, the more resistance it has. This is because the electrons must flow through more material, and therefore meets more friction over the entire distance.
(3) Cross Sectional Area
The resistance of a material is inversely proportional to the cross sectional area of the material. This means that the thicker the substance is across, the lower the resistance. This is because the larger the cross sectional area is, the less friction there is over a given length. (Picture in your mind, if you will, that a fire hose will pass more water than a garden hose, because the wider the pipe, the less resistance it has).
(4) Temperature
In various types of materials, resistance can vary inversely or directly with the temperature. This is because of the chemical properties of the material. In Carbon, for instance, the resistance decreases as the temperature rises. So we say it varies inversely. In copper, however, the opposite is true, with the rise in temperature, we have a rise in the resistance.

Resistance then, is basically a form of friction which restricts the flow of an electrical current. In basic science class, you learned that by putting your hands together, and rubbing them quickly, your hands get warm. This is because friction generates heat. Electrical friction - RESISTANCE - also generates heat.

So not only can resistance change with heat, but causes heat as well. An important point to remember when working with resistors, especially in high power circuits.

### 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 …