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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
There are many types of antennas, to many to mention, here is a list of the most commonly used:
Unidirectional Types:
First the most common is the, 1/4 wave whip.
Following types is popular for CB and Ham
The 1/2 wave dipole, two 1/4 wave wires or whips in line and center fed
1/2 wave folded dipole, two 1/2 wave wires inline folded back to the center also used for FM reception.
1/4 wave ground plain, a 1/4 wave whip with 3 or more horizontal ground plain elements (Balanced)
1/2 wave ground plain, a 1/2 wave whip with 3 or more horizontal ground plain elements (Balanced)
5/8 wave ground plain, a 5/8 wave whip with 3 or more horizontal ground plain elements but it need L/C turning where the transmission line enters the antenna at the bottom to balance it
Semi Directional
The radio ham's use the long wire antenna for long wave medium and short wave, it is a full wave length of wire, spanned horizontal between two poles or even trees or buildings center or end fed where the transmission line is connected to the center or the end of the wire.
The inverted V, is two 1/2 or 1/4 wave wires spanned from the top of a pole in an inverted v and anchored to the ground.
Directional types:
Multi element Yagi, very popular with radio ham's and TV reception
The quad loop, or cubical quad, also popular under radio ham's
The helical coil that is very popular in the higher frequency range because of it's compactness.
The Parabolic disk that is used mostly for WiFi, microwave and satellite communication
The Printed PCB loop that is used in remote controls and cell phones, it is a printed track on the PCB in many configurations and shapes, it is also used for blue tooth dongles Etc.
What is the difference between open loop and closed loop gains of an op amp?
A: Usually by looking at the specification for that op-amp and there will be accuracy deviation from device to device. To use it open loop is practically impossible all it tells from specification that there will be enough gain when the loop is closed and the max frequency available
What is a typical advantage of CMOS over TTL?
TTL stands for Transistor-Transistor-Logic. N-MOS is a type of a metal oxide semiconductor technology. TTL is faster, but generally uses more power. MOS based devices are slower, they and they use less power. Speed is an issue when dealing with high speed data processing.
Which circuit has different parts of the circuit on separate branches?
Any circuit that even has more than one branch is a parallel one.
What is the function of gate in FET?
u can think of it as two switches(a,b) in series if one is open current won't flow
or a*b
a b y
0 0 0
0 1 0
1 0 0
1 1 1
Is ohms law applicable to all the current carrying conductors?
Ohm's law is a linear approximation for the voltage versus current across a conductor. This approximation works very well for good conductors (like metals) as well as poor conductors (like wood), but not very well for semi-conductors (like Silicon).
The real power in a DC system is the product of voltage & current. P = V * I
In an AC system the power is equal to V * I * power factor. The power factor allows for the fact that the power is less than the volt-amps. This happens when the voltage and current are out of phase, i.e. if they reach their peak value at different points in the AC cycle. In fact if the phase difference is exactly 90 degrees, no real power is transferred at all, although the transmission wires still have to carry current and produce power losses as a result,
The real power (in watts) is defined as the volt-amps times the cosine of the phase difference between voltage and current. Using the convention of complex numbers, the 'imaginary' power (in volt-amps-reactive or VAr) is defined as the volt-amps times the sine of the phase difference.
The three quantities are connected by the Pythagoras formula:
(VA) squared = (watts) squared + (VAr) squared.
Why a transformer designed for a 120V AC input will often burn out if connected to a 120V DC source?
All transformers are designed to work on AC. They do not work on DC.
If you connect an inductor to DC, the current will increase until the capacity of the source or the conductance (1/resistance) capacity of the inductor and conductors is reached. Often, this condition will overheat and destroy the inductor, or destroy the source. A transformer is not an exception, as it is a form of inductor.
What muct be known to calculate current using Ohm's law?
I(current) = V(voltage)/R(resistence) Example : 220 V / 5000 Ohm = 0.044 A (Ampère) = 44mA
An XOR gate is an Exclusive OR gate. The output is 1 if either one or the other inputs are 1. but remains at 0 if both inputs are 1.
A normal OR gate will output 1 if both inputs or either is at 1.
XOR means exclusivly OR, one or the other but not both.
What is measured in amperes a current voltage or an Resistance?
Electrical current is measured in amperes.
What is the use of offset null in an opamp?
A: Any offset whether is voltage or current is an output error to contend with.
Why race condition occurs in sr flip flop?
it can be eliminated by using not more than two level of gating.
ANSWER: It can be eliminated by using grey code whereby there is only one transition of state before any other can occurs
Waves are non-stop, night and day, year after year, shaping the coast line.
Waves wear away/erode the coast by breaking the rocks around the land this creates less space for the land and gets smaller in time.
An intransic material is a material that have been used in doping process.There are two type of intrinsic material n type and p type.
What is the difference between electronic devices and electrical devices?
All modern day computers are built using electronic or semiconductor processors and components, so these are electronic systems which of course need electrical power to operate but are not in general put under category of electrical devices.
What are the health and safety tips when using a soldering iron?
Wear eye protection.
Never touch the element or tip of the soldering iron.
They are very hot (about 400°C) and will give you a nasty burn.
Take great care to avoid touching the mains flex with the tip of the iron.
The iron should have a heatproof flex for extra protection. An ordinary plastic flex will melt immediately if touched by a hot iron and there is a serious risk of burns and electric shock.
Always return the soldering iron to its stand when not in use.
Never put it down on your workbench, even for a moment!
Work in a well-ventilated area.
The smoke formed as you melt solder is mostly from the flux and quite irritating. Avoid breathing it by keeping you head to the side of, not above, your work.
Wash your hands after using solder.
Solder contains lead which is a poisonous metal.
What can be tested with a digital multimeter?
No. You must use a ground (earth) resistance tester, such as a earth-resistance megger. Apart from the practical requirements for making the test (too long to explain in this answer), a digital multimeter uses a DC supply, which acts to polarise the chemicals in the soil, giving false readings.
ANSWER: YES you can but only if there is appreciable Resistance to measure. THERE ARE MANY GROUNDS EARTH IS ONE OF THEM
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How do you convert 275 mA to amps?
As a milliampere (milliamp or just mA) is 1/1000th of an ampere, we can convert mA to Amps by just dividing by 1000. Another way is to take the current in mA and move the decimal to the leftthree places to accomplish the division by 1000. Here's the scoop: 275 mA / 1000 = 0.275 Amps Note that the decimal in 275 is to the right of the 5, and it's written as 275.0 (with a 0 added to show where the decimal is). Moving the decimal to the left three places gets up to .275 Amps, but we usually hang a 0 in front of the decimal. To convert Amps to milliAmps, just multiply by 1000 or move the decimal to the right three places. Just the opposite of what we did here to convert the other way.
What is the deviation ratio for frequency modulation?
Deviation ratio: In a frequency modulation system, the ratio of the maximum frequency deviation of the carrier to the maximum modulating frequency of the system under specified conditions
BCD refers to Binary Code Decimal there are no diagrams it is just a numbers system GRAY code is a means to make one reliable state to change at a time eliminating false coding because of transitions in counters and such
Why you do analog to analog conversion?
To isolate a patient from getting connected to stray voltages. An isolation transformer is used and batteries power it to further isolate you from the real world. Also for sensitive measurements to eliminate some of the noise and current loops.
