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Electronics Engineering
Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.
24,372 Questions
How does a photodetector convert a light signal into an electrical signal?
- photoresistor - resistance drops with brighter light
- solarcell - generates voltage when illuminated
- phototransistor - collector current increases with brighter light
- photomultiplier - anode current increases with brighter light
- etc.
Or did you want the physics?
Advantages of a full wave rectifier?
In half wave rectifier there are only two diodes connecting opposite to each other , hence their is possibility 0f only 90 degree phase will gane to us .thus we got the dc voltage wave . The half wave rectifier is cheaper one,it will give the pure dc.
The principle of an up converter is very simple: take a standard definition signal, examine each pixel of it and then calculate what each pixel on an HD signal would look like if the signal was HD. Making that simple process actually happen is rather more complicated. Very powerful signal processors are needed to study a block of pixels of the incoming signal. Typically, the block will be four or five pixels wide and high. The centre of the pixel block is the position of the new pixel to be created in the HD signal. The pixels of the original signal that are closest to the position of the new pixel have the most impact on the new pixel. The further away the original pixels are from the new pixel position, the less they affect the brightness and color of the new pixel. Once the original pixels are assessed and the new pixel has been defined and stored away, the process is then repeated for the next HD pixel. There is far more to the process than is described but that is the principle of up conversion. The additional processes are used to generate images without hard, ragged or jerky edges and mis-shaped detail in the new image. The techniques have been developed over several decades and were first used to convert North American signals to European and vice versa. Some thirty years on and the conversion quality has improved dramatically. Despite the advances, up conversion is not an exact science and is not a perfect process. It is important to remember that HD signals contain about 5 times as much information as SD signals. Putting an SD signal through an up converter does NOT increase the amount of detail in the image. In fact, an up converter will actually degrade the detail very slightly. Fortunately, when we watch an up converted signal, it is quite common that we get an impression of a better image than the SD original.
How many memory locations can be addressed by a microprocessor with 14 address lines?
2^14 memory locations. In general for n-bit address bus, its 2^n
What does the letter 'H' mean in electrical circuits?
It means generally "Hi"side of some electrical device (such as Hi -H- or Low -L- transformer side)
Where can you obtain a Denon AVR 2400 receiver manual?
A website is listed in the Related Links below with a scanned copy of the manual.
What is the value of resistivity?
Electrical resistance is measure in Ohms. A function of voltage divided by current. It is also dependant on the length and cross sectional area of the conductor.
What happens if gate voltage of an ON scr is decreased?
A: Nothing after an SCR conduct the gate has no more control to shut it off. So how do we shut off an SCR two way reverse the voltage on the SCR or reduce the current below the holding current. SCR are not DC friendly once on they stay on until see above
Why you use negative source in emitter biasing?
to get the base- emitter junction forward bias we should connect the negative of the diode with the negative of the battery and the positive of the diode with the positive of the diode so we should connect negative source in the emitter
= A Reactance Modulator =
A reactance modulator changes the frequency of the tank circuit of the oscillator by changing its reactance. This is accomplished by a combination of a resistor, a condenser, and a vacuum tube (the modulator) connected across the tank circuit of the oscillator as in Fig. 33 A, and so adjusted as to act as a variable inductance or capacitance. Fig. 33 A. Principle of a reactance modulator The net result is to change the resonant frequency of the LC circuit by amounts proportional to the instantaneous a.f. voltages applied to the grid of the modulator tube, without changing the resistance of the LC circuit or the amplitude of the oscillations. A modulator circuit is shown in Fig. 33 B. Fig 33 B. A reactance modulator The voltages supplied to both the modulator and oscillator must be carefully stabilized to prevent undesired frequency changes. The speech amplifier (Fig. 33 A) does not have to deliver any power and need supply only a small output voltage, say 10 or 15 volts. A pentode and triode, R-C coupled, will be sufficient even with a sensitive microphone and a high-powered oscillator. The frequency change of LC per volt change on the a.f. grid of the modulator tube will be greater when C1,Fig. 33 B, is made smaller. The blocking condenser C2 has a comparatively high value, and hence offers but small reactance to r.f. currents. Fig. 19 H. An RC phase shifter In Fig. 33 B, the radio-frequency voltages which are developed across the tank in the oscillator circuit also appear across the RC1 circuit and across the parallel 6L7 modulator tube. Now look up the phase-shifting circuit of Fig. 19 H. The resistance r has been replaced by the internal resistance of the modulator tube of Fig. 33 B. The voltage drop across C1 is 90° out of phase with the tank voltage. It is applied to the control grid of the 6L7 whose r.f. plate current responds in the same phase. Thus this current is made to lag 90° behind the tank voltage. The r.f. plate current flows through the tank circuit and, combined with the current therein, is equivalent to a new current whose phase differs from the normal value just as though an additional reactance (not resistance) had been connected in with L and C. This, of course, changes the frequency of the LC circuit and hence of the transmitter. When a.f. is fed into the modulator tube, it causes proportionate changes in the r.f. plate current and hence in the equivalent reactance of the LC circuit.
How do you increase the frequency in an oscillating mass-spring system?
You either Decrease mass or increase spring force.
In a power station where dc is actually converted to ac while distribution?
The generated voltage in a power station is AC voltage, not DC. So, it is never converted to AC, because it is already AC.
A frequency of 1GHz on a spectrum analyser corresponds to what frequency in the Ku band?
The Ku band of microwave frequencies ranges from 12 to 18 GHz. A frequency of 1GHz is not in the Ku band. There is no correspondence.
Is the 1GHz setting on the spectrum analyzer a center frequency? Or is it one of the ends of the spectrum analyzed? Is it the width of the spectrum being analyzed? And if it is the latter, what is its center? Knowing these things will still not change the answer given, but may help to "sort out" a possible problem with the question the way it is written.
A megger measures very high resistance to check insulation, therefore it must use very high voltages so as to detect the very small current flowing.
Find users manual for Olympus digital voice recorder vn-4100pc?
go here; http://www.olympus.co.jp/en/support/imsg/vtrek/download/manual/ws/man_ws100_ws200s.pdf
Can you substitute a 12bh7 vacuum tube for a 12ax7 or 12au7 or 12at7 or 12ay7?
All those tubes are double triodes, but their characteristics differ. This means that any of them could possible substitute another, but that would depend on the characteristics of the circuit in question.
An ideal voltage source charges capacitor in?
A: A voltage source Will charge a capacitor to 63% of its input value, The value to get there is stated a Resistance time capacitor as time. Mathematically it will never get there but engineering consider 5 times RC time constant as close enough,
The physical body of your DC Equipment is always your GROUND. This GROUND is where you also connect your -VE.
What is the significance of displacement current?
mne la aku taw.. kalo aku taw.. xdenyer aku nak google soalan nie... ape da ko.. admin xley pakai
