Electronics Engineering

A thermocouple is a temperature sensor, or more precisely measures temperature differences between two locations. Because it uses only wire in the sensing, it can be useful for measuring extreme hot or cold temperatures or in difficult environments.

A thermocouple works because of the thermoelectric effect. What's thermoelectric effect? Thank a cat named Seebeck for the answer. If a piece of metal is warmer at one end than at another, the temperature gradient (the difference in temperature) creates a tiny voltage and the voltage depends on the type of metal. In a loop of wire made from the same material, the voltage effect cancels. But if the loop contains two different metals the different parts of the loop produce different voltages ,and the voltage difference can be used to calculate the temperature difference. The voltage set up (usually a few microvolts or 1/1,000,000ths of a volt) is usable to measure temperature difference with an external circuit. The conversion from voltage to temperature is typically a complicated polynomial equation. And in this day and age, the electronics to measure and convert are cheap and the device is fairly accurate.

Since the thermocouple only measures the difference in temperature between two points, you also need a reference temperature measurement. In the old days, this was done with an ice bath (0 degrees C), but now usually another temperature sensing device is used.

Need something to measure temperature and talk to control circuits in equipment that is used to heat stuff? Like your oven, maybe? We've got just the ticket. It's a thermocouple temperature probe. Works well, lasts a long time and doesn't wear out.

Current relays are the relay which sens the current passing in particular circuit and operates when this current exceed its set value.

I recently came across one of these. It's a bandpass design(I believe) with some sort of 'active' compensation- It uses an "STK" chip. Seems to be a subwoofer with ability to also power front/rear speakers. I'd (also) like to hear/see more on this unit.

RTS (Request-to-send) packets are a mechanism used by the 802.11 wireless networking protocol which establish an open communiction to an AP or node. The client machine transmits the RTS to the AP which in turn sends a CTS packet (clear-to-send) back to the client. This prevents packet collisions, which are common among unmanaged high density networks. In most routers, the default setting for the RTS threshold will be around 500. Acceptable packet sizes range from 0 to 2'347.

While there may be very rare exceptions to this, nearly 100% of the time neutralization of an HF PA or power amplifier vacuum tube has virtually nothing to do with VHF or UHF oscillations. VHF oscillations are almost always caused by a high impedance (parallel resonant) path from a grid to ground. The high impedance prevents the grid from being "clamped" or held at ground potential for RF at some frequency or range of frequencies. If this high impedance resonance happens to occur at a frequency range where the anode path to ground is parallel resonant, the tube can act like a tuned-plate tuned-grid oscillator. Hope this helps! It is also called Unilateralisation:- it is a process by which neutralising or nullifing the internal feedback effect causing internally, by connecting an additional network. It is explained breifly in the related link.

Inductors are considered to be a load for reactive power, meaning that they will draw reactive power from the system. Capacitors are considered to be sourced of reactive power, they feed reactive power into the system. If you have a circuit that is at unity (balanced with inductors and capacitors) no reactive power will be drawn from the source. You will have unity power factor. If your circuit is more inductive than capacitive it will be drawing reactive power from the source. The opposite is also true for capacitors.

"E" indicates an error condition. This is generally caused by attempting a calculation out of the calculators possible range of answers, or by static electricity altering the memory contents. Try the AC (all clear) button, power on/off, removing and re-installing all batteries, using a straightened paper clip to depress the reset button (usually on the back of the calculator)

There are several examples of BEAM robots which are line followers. BEAM robotics uses simple logic chips for the "brain" like the 74AC240 which costs $1 or so. The rest of the components are discrete components which means no microcontrollers are involved - only the usual parts like diodes, resistors, capacitors etc. I've included 2 links in the "Related Links" section below.

Zero to 100 ohms.

There is a thermoelectric generator between the heat sink and combustion chamber. The generator produces power which, in turn, spins the fan(s) in the unit.

The stronger the magnetic field on your inductor the greater amount of current you will have flowing through your series circuit.

Emitter

Both hybrid integrated circuits and monolithic integrated circuits were used in third generation computers. These integrated circuits contained from 4 to 100 transistors per integrated circuit.

The image above shows hybrid integrated circuits of the type used in the IBM System 360 line of computers.

We see LEDs every day. They're in lotsa stuff. A light-emitting diode (LED) is a semiconductor diodethat radiates light (electoluminescence) when current passes through it in the forward direction. Electrons move though semiconductor medium and "fall into" other energy levels during their transit of the p-n junction. When these electrons make a transition to a lower energy level, they give off a photon of light. This photon may be in the infrared region, or just about anywhere across the visible spectrum up to and into ultraviolet - but we have to pick a color when we make them. That means we can get an infrared LED to work in our remote controls, and get other ones of different colors to make indicators or, in large arrays, displays - even color ones. LEDs uaually are made to emit one color of light, though bicolor ones and more can be fabricated. Intensity is being improved as well. That broadens the applications considerably (think vehicular tail lights). The device has a pair of leads, and a (usually) plastic body moulded around the leads and the semiconductor crystal itself. That way the light can get out through the plastic. There is frequently a "round dome" at the top of the LED which serves to focus the light headed out through it. Remember that it is the material of the semiconductor crystal that determines the light given off by the device. A normal LED isn't really voltage dependent. When obtaining the LEDs, a manufacturer or hobbiest specifies the color. Red, green and blue are most popular, and, though there are other colors, it might be tough(er) to find them. Note that the big LED color displays use a three-LED pixel, and by driving it (the 3-LED assembly) appropriately, a wide range of colors can be obtained. This in an introduction to the LED. An electronics student will review semiconductor fundamentals and then more closely examine the chemisty and physics of the particular p-n junction that is fabricated to exhibit electroluminesce. A link is provided to the Wikipedia article on the light-emitting diode.

The coherence bandwidth of a wireless channel is the range of frequencies that are allowed to pass through the channel without distortion.

yes

The Javac is the java compiler javac.exe is a process associated with Java(TM) 2 Platform Standard Edition 5.0 Update 5 from Sun Microsystems, Inc.. Java Capusal this is a java compiler

The LNB takes the signal reflected off the dish, sends that signal through the coax cable to the receiver, where the receiver decodes the signal unlocking the channels you subscribe to.

A lead acid cell has an off charge/no load voltage of 2.2 volts, so that 12 cells in series will have a voltage of 26.4 volts. When you float this across a charging supply, standard practice is to increase the voltage to 2.3 volts per cell, so that the total voltage becomes 27.6 volts.

Airplanes normally have a 27.6 volt DC system, and larger aircraft also have a 115 volt 400 Hz system. Also, rare these days, possibly a 115 volt wild frequency system.

Note that the so called 12 volt system in a car is actually 13.8 volts.

This just means that the semiconductor has extra holes in it. On the order of 10^6 I believe.

Rack server

LPF setting: typically 60-100Hz. Most use ~80Hz. Depending on the sub and the type of music You listen to, if set too low the sub won't put out the wanted frequencies; to high and power is wasted on higher frequencies.

Cosmic rays are constantly coming down, coliding with the electrically charged atmosphere witch creates a massive ionization screening in the ionosphere. A giant world wide electromagnetic umbrella!

Norton's theorem is the current equivalent of Thevenin's theorem.