Electronics Engineering

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The rubber or plastic serves as electrical insulation (because they are poor conductors). Without insulation, the electricity running in a bare cable would leap over into any other electrically conducting material it touched. With enough voltage, a human could be electrocuted.

Electrical signals would disappear and get lost, causing equipment to fail.

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So the conductor is insulated against possible metal contact & prevent a short if it's grounded.

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All household electric wires are covered with plastic and rubber. This is called insulation. It keeps the potential of the wire from returning to ground (short circuit) before being used by the load. The higher the potential (voltage) the greater the insulation factor has to be. Bare wires in transmission towers also use insulation in the form of air. To use this method, engineered clearances have to be maintained between the conductors.

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All electrical power wires are covered with an insulating material. This is to prevent the potential on the wire from going anywhere except to the load.

Electrical connecting wires are covered with plastic to prevent the wire under the covering from shorting out against each other or shorting out to ground. The electrical terminology for this covering is the wire's "insulation".

These days most electrical wires are covered with a flexible plastic (rubber starts with the sap from a rubber tree; plastic usually starts with a petroleum base).

Answer

The main purpose of the "cover" (insulation) is to keep the wire from shorting to other objects.

The plastics used generally have a good mix of the following properties:

It is flexible so the wire can be flexed and bent.

It is inexpensive and easy to apply to the wire during manufacturing.

It has resistance to chemicals and UV light.

Sometimes it's also important for it to resist abrasion or temperature extremes, or submersion in water.

You can get wire with different types of insulation depending on what you need it to withstand.

N-type semiconductor materials which have free electrons,(which are negatively charged).

P-type semiconductor materials which have too few electrons. Therefore the opposite of electrons - holes (which are negatively charged).

You can think of it like positive and negative poles of a magnet.

There are five wind farms in Kansas, USA, with a total of 1028 turbines.

1. Caney River Wind Project
2. Ironwood
3. Meridian Way
4. Post Rock
5. Smoky Hills Wind Farm

Amplitude Modulation, AM, is a technique where a high frequency carrier of constant amplitude and frequency is modulated by a lower frequency signal. This modulation varies the amplitude of the carrier, and the resultant modulated carrier is what is transmitted. A typical carrier in the standard AM broadcast band is 550 kilohertz to 1.6 megahertz, while the modulating signal is audio, in a range less than 20 kilohertz.

Demodulation involves tuning the centerpoint of the carrier and detecting the envelope of modulation, often with a peak follower such as a diode, capacitor and resistor. Very simple AM radios can be built with only a few components, typically with less than six.

While there are several demodulation techniques, by for the most common is the superhetrodyne technique. Since selectivity and sensitivity are opposing factors, the RF stage of such a receiver generally trades selectivity for sensitivity, simply boosting the gain with a middle of the road semi-broad band amplifier. Then this is mixed with a local oscillator that is tuned to be exactly 455 kilohertz away from the desired carrier frequency. The mixed signal then is shifted to a center point of 455 kilohertz.

This is followed by a very steep skirt band pass filter, the IF stage, which filters out everything but the desired shifted carrier. This is where the selectivity comes in, and since the IF stage is tuned to only one frequency, it can be highly optimized. Actually, the IF stage is three stages, each tuned to slightly different frequencies, so that the response curve, while having steep skirts, and centered at 455 kilohertz, still has the bandwidth necessary to cover the audio range needed.

The output of the IF stage is then demodulated using some kind of peak follower, and the output is the original signal.

If you analyze the frequency domain of the modulated carrier, you discover that there is a carrier, and two side bands. The carrier contains no information, and consumes about 67% of the total power, while each side band carries the exact same information, but each is backwards to the other.

This has led to improvements in design. Sometimes you can suppress the carrier prior to the final amplifier in the transmitter. This gives you the ability to put more power into the side bands. The down side is that the receiver is more complex, and has to regenerate the original carrier and mix it with the suppressed carrier signal before then mixing it for the downshift into the IF stage.

You can take this even further, by suppressing both the carrier and one of the sidebands, since all of the signal is contained in both sidebands. Of course, this makes the receiver even more complex.

Some CB and Amateur radios are single sideband suppressed carrier, simply known as SSB, in order to boost range. Most broadcast stations are double sideband non-suppressed carrier, simply known as AM, in order to simplify the receiver. Different areas of the world use slightly different terminology, such as SSB-SC, but the intent is the same.

You are wagging the wrong end of the dog. A power supply that is constant voltage (the regular ones) may have a LIMIT of 3A at a certain voltage. The reduce the current you either turn down the voltage or add a resistor E=IR to the circuit.

I would put together an ancillary, current limiting, circuit which could be connected across the output.

AC current fluxuates that is why it is called alternating current. DC does not fluxuate that is why it is called direct current.

If I waggle the voltage control up and down on a d.c. power supply to which a resistor is connected, the current willfluxuate. (Quite poetic, but I prefer to say fluctuate.)

An a.c. changes direction rapidly and continuously, i.e. its direction alternates.

That's why it is called alternating current.
AC current Or alternating current is constantly switching from plus to minus While DC current or direct current moves from minus to plus.
AC and DC refer to Alternating Current and Direct Current respectively. AC is the movement of electrons through a conductor while switching directions, while DC involves electrons moving steadily in a particular direction.

The main advantage of alternating current (AC) over direct current (DC) is safety.

DC locks you onto the current AC throws you away as it alternates.

AC was invented by Nikola Tesla.

actually there are many:

1. solder wick
2. solder sucker
3. soldering iron and lead bending tool
4. hot air reflow (one of best, can remove devices with hundreds of pins easily)
5. hot bar
6. propane torch and vice-grip pliers
7. etc.