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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
When a switch is on is a circuit open or closed?
If the switch is what is keeping the load from turning on, then yes, there is a voltage across the open switch.
Why we want to improve the power factor?
The best way to improve power factor is by adding capacitors. Low power factor is due to reactive loads (motors, pumps, etc.) that are connected to your electrical system.
ADDITION
The best way to improve power factor in the case of motors is to use a motor drive, like a Variable Frequency Drive. These drives allow very precise control over a motor, unlike the very sudden, jerky starting and stopping across the line seen when using a motor starter. They eliminate the huge inrush current required to start motors that causes low PF.
Answer:1) Power factor can be calculated by connecting an energy meter [P] (voltage coil in parallel & current coil in series with the load), a voltmeter [V] across load and an ammeter [A] in series with the load. Measure P, V & I.
Since, Active Power (P) = V.I.Cosϕ
power factor = Cosϕ = P/VI
2) Power factor is usually (industrially) improved by connecting a shunt (parallel) capacitor bank at feeding end.
How it works??
Inductive loads contain both inductors and resistors. But due to phasor difference of coils and caps when voltage is applied across both, the two currents results in a smaller net current finally. So now the angle (ϕ) between the voltage phasor and current phasor is lessened. When ϕ is reduced, Cosϕ is risen resulting in a higher power factor.
In a series circuit the is the same at every point?
In a series circuit, components (such as resistors, bulbs, or other devices) are connected end-to-end so that there is only one path for the current to flow. Because there is only one pathway for the current, the same current passes through each component in the circuit.
This principle is derived from the conservation of electric charge. Since charge cannot accumulate or disappear in a closed circuit, the current that enters a component must be equal to the current that exits that component. In other words, the flow of current is continuous and consistent throughout the series circuit.
Mathematically, this can be expressed as:
I_total = I_1 = I_2 = I_3 = ... = I_n
Where:
I_total is the total current entering the series circuit.
I_1, I_2, I_3, ..., I_n are the currents through each individual component in the circuit.
It's important to note that while the current remains the same throughout a series circuit, the voltage (potential difference) across each component can vary depending on its resistance or impedance, according to Ohm's Law (V = I * R).
Georg Simon Ohm was a German physicist and mathematician who is best known for formulating Ohm's law, which states that the current through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them
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What are the inputs to an op amp?
Power Supply Pins: Op-amps require power to operate. They have positive and negative power supply pins (+V and -V) that provide the necessary power levels for the op-amp to function.
Output Pin: The output pin provides the amplified or manipulated signal based on the inputs. It's where the result of the op-amp's operation is obtained.
Offset Null or Offset Adjustment Pins: Some op-amps have offset null pins that can be used to adjust the output offset voltage. This is useful for minimizing any unwanted voltage offset in the output.
Frequency Compensation Pins: In some op-amps, additional pins are used for frequency compensation to ensure stable operation in high-frequency applications.
Balance or Trim Pins: These pins are used in op-amps that are intended to be used in bridge or differential amplifier configurations, where precise balance between inputs is necessary.
What were the two main problems caused by using the valves on the Colossus computer?
Probably rate of burnout and heat. But this was common to all vacuum tube computers, not just Colossus.
How much did he first desktop computer cost?
The first computers had no fixed selling price. They were usually built on cost plus fixed fee contracts, because the people making them could not guess at final cost to build them.
For example the ENIAC was estimated at $50,000 when the Army signed the cost plus contract. The Army eventually payed a bit more than $500,000.
The UNIVAC I original fixed price contracts were for $250,000 but when the machine went into production its actual price was $2,500,000. Remington Rand lost lots of money on the first two UNIVAC's sold as the company had to pay the difference between cost to build and what the customer payed!
Why you use silicon chips in computers?
why we use silicon chips in computers?
- Silicon is cheap, it comes from sand.
- Silicon has a very wide operating junction temperature range (-55C to +150C).
- Silicon is very easy to process to make transistors and ICs.
- Silicon dioxide is an insulator, no other semiconductor has a solid insulating oxide.
- When circuits are built on a silicon chip they are either analog or digital building block circuits.
- The digital building blocks naturally build computers (especially now that we have building blocks as large as whole multi-core CPUs, etc.).
Before semi-conductors were used in computers, they had to use vacuum tubes which cost a lot, took up a lot of space, burned out quickly and so were unreliable, and used a lot of electricity. We could not have the modern computer without chips.
they are;small,compact and portable.
Silicon is the easiest elemental semiconductor currently usable to make ICs with. One of its most important properties is its oxide and nitride are insoluble solid insulators, this is not true for either germanium or carbon the other elemental semiconductors. Also silicon has a good operating temperature range (junction temperature up to 150C), germanium has much lower range and although carbon (as diamond) has much higher range (junction temperature up to 600C) it is too brittle for current process machines. All other semiconductors are alloys and are tricker and more expensive to process than elemental ones. Most important silicon is almost free, it can be extracted from any sand, the parent rock of sand, and of course sandstone which is made of sand.
What advantage over vacuum tubes did transistors represent in computer design?
From an audio amplifier standpoint, transistors were primarily low-voltage, high current devices. Since loudspeakers were typically low-impedance, the transistorized circuit didn't require a transformer to help match the impedance; i.e. they were better matched. However, when a transistor "saturated" it "clips" abruptly, causing harmonics at the output. Vacuum tubes tended to "soft clip' which reduced the undesirable harmonics.
From another standpoint, transistors were smaller in size, didn't require high voltage power supplies, and dissipated less heat (i.e. more efficient).
Analog computers are also called continuous computers, as there are no discontinuities in their computations. A mechanical analog computer might represent variables by rotation rate of shafts, any given shaft can rotate at any speed and will smoothly accelerate or decelerate its rotation as the calculation proceeds. An electronic analog computer might represent variables by voltages, say any voltage between -20VDC and +20VDC with voltages smoothly varying as the calculation proceeds.
- Bush differential analyzer at MIT, electromechanical, 1929.
- Norden bombsight, electromechanical, 1930s through 1960s (used in WW2, Korea, and Vietnam!).
- Various commercial electronic differential analyzers sold from 1950s through 1970s, electronic.
- Murray/Walker simultaneous equation solver, electronic, 1949.
- Vacuum operated cruise control in cars, mechanical/pneumatic.
- Resistor/capacitor 3D mesh water table models, electronic.
- etc.
Digital computers on the other hand have discontinuous states that they jump from one to another.
- ABC: Atanasoff-Berry Computer, simultaneous equation solver, 1942
- ENIAC, late 1945
- UNIVAC I
- IBM 700 and 7000 series
- DEC VAX
- Desktops and laptops
- Both of the computers in your cellphone
- etc.
Hybrid computers are simply computer systems that combine both analog and digital computers together. Usually the digital computer controls the analog computer, reconfiguring it and entering new data each time the analog computer completes one problem, to have it solve a different one.
- Most were custom "one off" systems built by individual labs or universities by buying a standard COTS digital computer and a standard COTS electronic analog computer, and customizing them to work together as needed.
- One example of such a machine used a DEC minicomputer and an analog computer to model heat flow from a nuclear reactor fuel rod to circulating coolant. The analog computer was programmed on its plugboard to do a rapid solution through a single radial slice of the system, the digital computer was programmed to enter new parameters into the analog computer for each slice starting at the coolant entrance end of the fuel rod and collect and record the results of each slice. The machine could solve the problem to adequate accuracy much faster and more cheaply than an all digital system or all analog system of the time period.
Why the first-generation of computer use vacuum tubes?
- The first digital computer that used vacuum tubes was the ABC, completed in 1942 by Dr. John Vincent Atanasoff and Clifford Berry in Ames, IA.
- An early analog computer that used vacuum tubes was the Differential Analyzer, completed in 1929 by Vannevar Bush and a large team at MIT. (there probably were other smaller analog computers of this type that used vacuum tubes before this, so it probably isn't the first but its the earliest where I can find it clearly documented).
When was radar first used in world war 2?
One of the first uses was during the Battle of Britain. British radar would detect oncoming German airplanes and the British would send up the Supermarine Spitfire to shoot down fighters and the Hawker Hurricane to shoot down bombers. Radar let the British use their aircraft to their best advantage. Instead of constantly flying air patrol, they could take off when the enemy was coming, and attack them where they were. It was the advantage of radar that enabled the British to defeat the Germans and showed once and for all time, the importance of radar in air combat.
What happens to the current in a circuit when the resistance is increased?
The flow of electrons meets an increased impedance to it's flow.
Where was the overhead projector invented?
A man named Jenkins, not sure of the first name, made various technical improvements in Movie Projectors in the twenties. He was also an aircraft pilot of the experimental type- light seaplanes, as I recall, and WA ssomething of a TV pioneer as well, a versatile inventor! Jenkins Radiovision was his big, but somewhat obscure (Hit) a form of television device.
Is the word North Star capitalized?
Yes, it is a word. I am almost completely sure it is the study of astronomy.
The time constant of a circuit that contains inductance and resistance follows what type of curve.?
1.cosine 2.exponential
3.min-max value
4.sine
What is the function of an IC UM3561?
it is used to generate 4 kinds of sounds-police siren,fire alarm,ambulance and gun siren
Purely additive. 2+3+4+5+6=20.
Least Significant Bit. Least Significant Byte. (Depends on use.)
Do LCD TVs use cathode ray tubes?
Some early flat screen TVs used cathode ray tubes, but the flat faced tubes were harder to make and heaver than the older curved faced tubes. When newer designs (e.g. plasma, LCD, LED) came out that naturally produced flat screens and were lighter weight than cathode ray tubes, they rapidly made flat screen cathode ray tube TVs obsolete.
