0
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
What are the various types of sensors used to measure pressure?
Bourdon Tube.
· Spring and Piston.
· Bellows and capsules.
· Diaphragm
Is square wave inverter harmful to tvs?
The square wave inverter can be harmful to any device that has an AC to DC power supply, which almost every device does, because the slope of the incoming waveform is higher than usual and the interception point of the ripple waveform with the incoming waveform when the diode turns on can can high current transients in the diode. The can be minimized somewhat by using a series inductor to filter the high current transients.
What causes signal attenuation in copper cables?
Signal in a copper wire is simply continuous electric current (commonly referred to as electricity), whether alternating current (AC) or direct current (DC). It is not different than the electric power transmission lines that carry electric energy (or power) from power plants to distribution companies and houses.
Continuous electric current is the net motion of free electrons that are a part of the atomic structure of every conductor (i.e. metal). In the absense of an electric field, free electrons are in random/chaotic/thermal motion within the conductor, i.e. they are moving randomly and very fast. When an electric field is applied, they start moving under the influence of the applied electric field (i.e. in a net direction), extremely slowly compared to their random motion, but moving nonetheless. This net motion of free electrons is what is referred to as "continuous electric current".
If signal is continuous electric current, and continuous electric current is the net motion of free electrons, then signal attenuation is fading of this net motion.
What resists to the net motion of free electrons is the fixed atoms on the lattice structure. The "flowing" free electrons collide with fixed lattice atoms and cause Ohmic heating (a.k.a. Joule heating). This explains the resistance of the cable, which is the reason of signal attenuation. As the signal travels on the cable, the voltage level will decrease due to "copper losses" (i.e. ohmic heating). Resistivity increases with length (and decreases with diameter), therefore the longer the cable, the higher the resistance (and attenuation).
Near-field electromagnetic fields around a current carrying wire traps the free electrons to the outer shell of the wire. This is referred to as "skin effect". This effectively decreases the cross-sectional area, which in turn increases the resistance, and which in turn increases the signal attenuation. Skin effect becomes more effective at higher frequency signals flowing through the wire. Therefore, higher frequency signals flows through a higher resistance and thus gets attenuated more.
Note that fading (i.e. attenuation) of the signal is not the only problem in signal transmission. When a signal is sent, it should arrive at the load (i.e. destination) above some treshold power (i.e. not attenuated too much), and it should arrive undistorted (i.e. not interfered with too much). These are the two concerns:
- attenuation
- interference.
Reactance of the conducting medium (i.e. the cable used) or external electromagnetic fields can interfere with the signal. Cable's reactance comes from capacitance and inductance of the multiple wires isolated (to a degree) from each other within the cable.
That's it for now, my friend ;]
t
What is happening when voltages is applied on thermocouple?
Voltage is not intended to be applied to a thermocouple. Heat is, and that will result is a voltage being developed which can be used to measure the heat.
Actually what will happen depends on the polarity of the voltage applied to the thermocouple. One polarity will heat the thermocouple, the opposite polarity will cool the thermocouple. This phenomenon can be used to make a tiny refrigeration system needing no refrigerant fluid or moving parts (other than a fan to expel the unwanted heat) called a thermoelectric cooler.
A practical thermoelectric cooler is not built with ordinary thermocouples used to measure temperature or generate electricity. Instead it uses large thermocouples having a contact area between the dissimilar metals measured in square inches. Two of these large thermocouples are connected back to back in opposite polarity with a thermal insulator between them. When power is applied, one gets cold while the other gets hot.
Thermoelectric coolers are used in microprocessor heatsinks and in small portable refrigerators that are powered from a car's cigarette lighter outlet. In fact most of these small portable electric refrigerators have a switch that reverses power to the thermoelectric cooler, making it a heater instead; thus they can keep food either cold or hot, whichever is appropriate.
How does a backward wave oscillator work?
The BACKWARD-WAVE OSCILLATOR (BWO) is a microwave-frequency, velocity-modulated tube that operates on the same principle as the Traveling Wave Tube. However, a traveling wave that moves from the electron gun end of the tube toward the collector is not used in the BWO. Instead, the BWO extracts energy from the electron beam by using a backward wave that travels from the collector toward the electron gun(cathode). Otherwise, the electron bunching action and energy extraction from the electron beam is very similar to the actions in a Travelling Wave Tube.
The typical BWO is constructed from a folded transmission line or waveguide that winds back and forth across the path of the electron beam, as shown in figure.
The folded waveguide in the illustration serves the same purpose as the helix in a Traveling Wave Tube(TWT). The fixed spacing of the folded waveguide limits the bandwidth of the BWO. Since the frequency of a given waveguide is constant, the frequency of the BWO
is controlled by the transit time of the electron beam. The transit time is controlled by the collector
potential.
Thus, the output frequency can be changed by varying the collector voltage, which is a definite advantage. As in the TWT, the electron beam in the BWO is focused by a magnet placed around the body of
the tube.
What are the future scopes of CNC machines?
① digital platform. ② high-speed operation. ③ processing of high refinement. ④ functional composite. ⑤ intelligent control. ⑥ high-performance servo drive control.
Why do historians need to be careful about bias?
Historians Have To Be Careful Of Bias Because, If They Are Writting A Report About Something That Has Happened That Is Part Of History, They Might Use Bias Because They Want The Story To Be Remembered Or Famous In Some Way. But They Don't Want To Use Too Much Bias Because It May Not Be True !
advantages- don't have to change the machine in order to adjust it, just change the program.
disadvantage- your program could be wrong or screw up.
Why one farad capacitor is not possible?
its not possible because if we take charge= 1F and d= 1mm than the oppositely charged plates will require so much large area .the area is so much large that it becomes almost equal to mount everest
Why does resistance of human body decrease to electricity when body is wet?
If you increase resistance, current is restricted (river is damed up).
If you decrease restistance, current flows faster (river is wide and open).
With water on our skin the current can travel across our skin instead of having to move through our bodies. The current has found a new path. Not inside our bodies but outside our bodies where there is much less resistance.
Which is better?
A large highway with a traffic jam
or the side road next to the highway with the traffice jam
The side road is effected by the traffic jam, but is still faster than the highway.
oa79 is frequency diode... it pass only the bit of frequency..
What is the term for conductance?
Conductance is the inverse of resistance. The abbreviation is the mho, which is ohm spelled backward. The symbol is the upside down Omega symbol.
If you failed you ESD then the reasons could be:
- Your teacher did not teach you properly
- You did not work hard enough to pass
- You a simply not clever enough to pass
- Poor exam thechnique - you did not answer the questions the ESD actuall asked.
What is one time constant of a 4.7 μF capacitor in series with a 22 kΩ resistor?
The time constant of a 4.7 µF capacitor in series with a 22 KΩ resistor is about 103 ms.
Why is the resistance vs current graph is not linear?
resitance is inversly proportional to current when (v) is kept constant
<><><><><>
Because resistance is a function of temperature.
Because that is the definition of a latch.
A J-K flipflop is master-slave triggered because that is the definition of a J-K flipflop.
A D flipflop is edge triggered because that is the definition of a D flipflop.
The voltmeter has an internal resistance, which should be as high as possible. As this resistance draws current from the circuit under test, it will affect circuit operation. This is more pronounced in a high impedance circuit because the current drawn flows through higher resistances.
Why a transistor is used as a amplifier and switch?
transistor has 2 output 1 and 0 so can be used as a switch
Why the dynamic resistance of a zener diode different from its static resistance?
The dynamic resistance of a diode, be it zener or otherwise, will be different from its static resistance because a diode is not a resistor, and resistance is not a function of current flow. It is a diode, and a diode has its own characteristic voltage to current curve, forward and, in the case of a zener, reverse.
What is the advantage of an ayrton shunt ammeter over a multirange ammeter?
to increase the sensitivity for the same damping torque
