Electronics Engineering

Dalton's second theory was disproved by j.j. Thompson and ernest rutherford because dalton did not do any experiment to came out with that's theory,that is the reason why they came out with cathode ray tube and gold fuil apparatus.

A core in fiber optics is a single strand of fiber. It forms one half-duplex channel, where one transmitter can send data to one receiver. In order to form a full-duplex channel, two cores or strands are required. Many fiber optic cables contain many cores organized in many bundles.

The embedded system was invented in the mid 1980s. However, it was not really used in personalized computers and robots until the mid 90s.

Ceramic resistors as those that use ceramics to control a resistor's resistive value. Ceramic resistors are made of a combination of finely powdered carbon and ceramic material. These two powders combine in specific ratios to determine the final value of the resistor.

Ceramic resistors are widely used in many different types of electronic circuits and devices. While these types of resistors can endure very high operation temperatures, they also create significant amounts of electrical noise. Due to this fact, a ceramic resistor seldom finds use in sensitive radio receivers or other devices particularly susceptible to interference.

a signal source is a function it can be square , triangle sine and any combination of the three

An even amount on both sides of the valence band

0 to 360 a complete circle is one cycle

Magnetic amplifiers and vacuum tubes don't need transistors to amplificate electricity current. You can get a transistor by two oppositely connected diodes.

Capacitors resist change in voltage. By definition, the equation is dv/dt = i/c, or rate of change of voltage in volts per second is current in amps divided by capacitance in farads. In order for the voltage to go to zero instantaneously, then dv/dt must be infinity, which means i/c is also infinity. If capacitance is non-zero, then current must be infinity. Since there is no perfect voltage source, or no resistor or wire with perfect zero ohms, then it is impossible to have an infinite current, so it is impossible for the voltage across a capacitor to go to zero instantaneously.

I believe that is resistor transistor technology TTL transistor transistor logic

(B)usiness (T)elephone (S)ystems

i.e. Mitel, Shoretel, NEC, Inter-Tel (now Mitel), Avaya, Lucent, Cisco, Alcatel.. etc etc.

BTS - Base Transceiver Station

The lines of flux are crowded at the ends of magnets, this phenomena is called fringing.

Capacitor coupling involves the use of coupling capacitors.Coupling capacitors are mostly ceramic capacitors.These are in the range of 0.47picofarad to 4.7 microfarad.Never use an electrolytic capacitor for coupling.It is meant for bypassing.coupling capacitors aloow AC and block DC components of a DC coupled signal.This DC component may also include noise,a grounded voltage signal or a step function.The analysis of the circuit involves determining the h-parameters of the amplifying stages,the Fourier transform of the signal applied and at various points of the circuit and the Laplace transform of the circuit sections in order to know the conditions of operations .Using complex engineering mathematics,the time varying analysis can be performed .This makes use of the Maxwell's equations to know the fields of the passive and active elements.

In logarithmic quantization, one does not quantize the incoming signal but log of it to maintain signal to noise ratio over dynamic range.

Dr Inayatullah Khan

Thermal noise, also called Johnson noise.

It is caused by the collisions between electrons. These collisions are due to the random motions of electrons because of heat exchange. The absorption of heat energy charge the electrons with kinetic energy which energizes electrons into random collisions. These collisions are what we know as resistance in all conductors. But also will the electron density throughout the conductor vary randomly. The random movement of charges will occur throughout the entire conductor. The movement in electron densities will cause random fluctuations in voltage across the conductor.

These fluctuations in voltage will be directly due to the motions of electrons and will cover the entire frequency spectrum with a flat spectral density right up to about infrared frequencies where quantum mechanical effects will limit the noise bandwidth and so noise power will not become infinite. The noise is said to be a white noise. But self-inductance and self-capacitance that exist in all practical resistors and conductors will also probably limit the bandwidth before it gets to those extreme frequencies.

Heat absorption cause kinetic energy in electrons and cause random collisions, which determine resistance and thermal noise across conductor.

Most important is that thermal noise are only due to the collisions in electrons in random motion due to the kinetic energy gained by heat exchange, which is exactly what the resistance of the conductor is. These two parameters are directly related.

The reactance found in capacitors and inductors has absolutely nothing to do with collisions and kinetic energy of electrons or the processes involved.

Reactance is about the ability of the device to store energy in a magnetic field (inductive) or in a electric field (capacitive). It's all about other physical aspects such as the turns of wires, or dielectrics for a particular rate of change in voltage.

Collisions in electrons have no affect on those reactance parameters whatsoever and therefore will not influence thermal noise in any way. Because the factors that give rise to reactance are independent from the amount of collisions in the conductor or resistance. We can observe that X­L=2.Pi.f.L and that inductance of a solenoid is L=uoN2A/l. In this example of inductive reactance, there is not one single parameter from turns of wire and physical dimentions right up to reactance that contain the key element of R (resistance) since thermal noise voltage is defined as:

En2=4RkTBn

En= noise voltage

R= Resistance

Bn=Bandwidth

K= Boltzmann constant = 1.3806503 × 10-23 m2 kg s-2 K-1 or in short J/K

T= Temperature in Kelvin = °C + 273.15

Capacitors and Inductors do have some collisions of electrons due to heat exchange and that forms the resistive component of the device Z= r +jX and the resistive component does generate thermal noise, normally very little, but the reactance component that store energy in magnetic or electric field have nothing to do with it.

Furthermore the reactance's in a resistive network could influence the frequency bandwidth or rather, spectral density function that will determine the bandwidth. The bandwidth Bn will however be a major factor in the total noise power since the noise power is the total area under the spectral density function.

One may also note, that even if one would connect a resistor in parallel with some form of reactance that there will be no power exchange between a resistor and a reactance. This is because a reactance cannot dissipate power.

One can also not gain free energy in normal conditions from a thermal noise power since you will require resistance to dissipate power, which in return, in thermal equilibrium, generate a noise power back. Thus, it will receive as much noise power as it provides.

No difference only magnitude

A parallel branch is a current path. In general, current follows paths, voltage drops across components, and resistance is the voltage divided by current of specific circuit elements.

Teleglass T3-F HMD. It's 0.24 inches across. Oh, and you wear it like glasses. Borg-style.

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security lights use resistors as the light out side falls the security light turns on and as it gets lighterbout side the light dimms and turns off, in bmw's the resistors are used to detect when the lights should come on as light gets brighter the car lights turn off.

There was a time long ago when all broadcast stations (they were all AM at the time) shut down at sunset. That gave their engineers all night to repair or test the equipment, use the tower to work ham radio, etc. Until relatively recently, many stations reserved a 'maintenance window' on Sunday night, for example from Midnight until 5:00 Monday morning, for equipment maintenance if they needed it. Nowadays, the vast majority of stations are on the air 24/7, and they don't do any testing. The last remaining regular test procedure is in the case of a station that keeps a standby transmitter standing next to the main transmitter. They will typically operate on the standby once a week for a few hours, just to keep the dust off of the filaments, and make sure the standby is in working condition in case they need it.

The freqeuncy (or pitch) of the sonar is not generally the factor which is likely to effect wildlife, but the amplitude (how loud it is).

A SCR is a Silcon Controlled Recifier. It is a four layer device that can be conceptually considered to be two transistors in latch up configuration. (Though not exactly) For an SCR, there will be no conduction between anode and cathode until the gate / cathode junction is biased on. At that point, the SCR will latch up and conduct from anode to cathode, regardless of further changes on the gate. This condition will persist until the anode / cathode voltage drops to zero. The SCR can be used as a half wave dimmer in an AC circuit. If you want full wave operation, you need to use a bridge rectifier around the SCR, or use a TRIAC/DIAC circuit.

It's very easy to draw an electric circuit in Microsoft Word. You just need to open up the graphics menu from the top, and you'll get access to the drawing tools for circuit drawing.

The High current source otherwise known as the supply, can handle any low current device or low current load as long as the voltages are the same. The higher the Supply current or as you call the source the better for any device/load