praj-17/QA-MCQ-Open-ended huggingface dataset:
Title: Capacitor
Context: Daniel Gralath was the first to combine several jars in parallel into a "battery" to increase the charge storage capacity. Benjamin Franklin investigated the Leyden jar and came to the conclusion that the charge was stored on the glass, not in the water as others had assumed. He also adopted the term "battery", (denoting the increasing of power with a row of similar units as in a battery of cannon), subsequently applied to clusters of electrochemical cells. Leyden jars were later made by coating the inside and outside of jars with metal foil, leaving a space at the mouth to prevent arcing between the foils.[citation needed] The earliest unit of capacitance was the jar, equivalent to about 1.11 nanofarads.

question: Who was the first person to connect several Leyden jars in parallel? 

answer: Daniel Gralath

question: Where did Benjamin Franklin believe the charge was stored in Leyden jars? 

answer: stored on the glass

question: Who coined the term "battery"? 

answer: Benjamin Franklin

question: How many nanofarads did the earliest unit of capacitance equate to?  

answer: 1.11 nanofarads

question: Why was a gap left at the mouth of Leyden jars? 

answer: to prevent arcing between the foils
Title: Capacitor
Context: Since the beginning of the study of electricity non conductive materials like glass, porcelain, paper and mica have been used as insulators. These materials some decades later were also well-suited for further use as the dielectric for the first capacitors. Paper capacitors made by sandwiching a strip of impregnated paper between strips of metal, and rolling the result into a cylinder were commonly used in the late 19century; their manufacture started in 1876, and they were used from the early 20th century as decoupling capacitors in telecommunications (telephony).

question: Besides porcelain, paper and mica, what other non conductive material was used as an insulator?  

answer: glass

question: For what use were non conductive materials used in the first capacitors? 

answer: as the dielectric

question: What was layered between strips of metal in order to create paper capacitors? 

answer: strip of impregnated paper

question: When were paper capacitors first manufactured? 

answer: in 1876

question: What other use did paper capacitors serve in the telecommunications industry? 

answer: as decoupling capacitors
Title: Capacitor
Context: Charles Pollak (born Karol Pollak), the inventor of the first electrolytic capacitors, found out that the oxide layer on an aluminum anode remained stable in a neutral or alkaline electrolyte, even when the power was switched off. In 1896 he filed a patent for an "Electric liquid capacitor with aluminum electrodes." Solid electrolyte tantalum capacitors were invented by Bell Laboratories in the early 1950s as a miniaturized and more reliable low-voltage support capacitor to complement their newly invented transistor.

question: Who invented the first electrolytic capacitor? 

answer: Charles Pollak

question: In what sort of electrolyte does the oxide layer on an aluminum anode remain stable? 

answer: a neutral or alkaline electrolyte

question: In what year was the patent filed for an electric liquid capacitor? 

answer: In 1896

question: What sort of capacitors were created by Bell Labs in the 1950's? 

answer: Solid electrolyte tantalum capacitors

question: Why did Bell labs create their new type of capacitor? 

answer: to complement their newly invented transistor
Title: Capacitor
Context: Last but not least the electric double-layer capacitor (now Supercapacitors) were invented. In 1957 H. Becker developed a "Low voltage electrolytic capacitor with porous carbon electrodes". He believed that the energy was stored as a charge in the carbon pores used in his capacitor as in the pores of the etched foils of electrolytic capacitors. Because the double layer mechanism was not known by him at the time, he wrote in the patent: "It is not known exactly what is taking place in the component if it is used for energy storage, but it leads to an extremely high capacity.".

question: What are electric double-layer capacitors called today? 

answer: Supercapacitors

question: When were low voltage electrolytic capacitors with porous carbon electrodes invented? 

answer: In 1957

question: Who invented low voltage electrolytic capacitors with porous carbon electrodes? 

answer: H. Becker

question: In what part of the capacitor did Becker believe the charge was being stored? 

answer: in the carbon pores

question: In what component of electrolytic capacitors did Becker believe was similar to the porous carbon electrodes? 

answer: the pores of the etched foils
Title: Capacitor
Context: A capacitor consists of two conductors separated by a non-conductive region. The non-conductive region is called the dielectric. In simpler terms, the dielectric is just an electrical insulator. Examples of dielectric media are glass, air, paper, vacuum, and even a semiconductor depletion region chemically identical to the conductors. A capacitor is assumed to be self-contained and isolated, with no net electric charge and no influence from any external electric field. The conductors thus hold equal and opposite charges on their facing surfaces, and the dielectric develops an electric field. In SI units, a capacitance of one farad means that one coulomb of charge on each conductor causes a voltage of one volt across the device.

question: What type of area is between the two conductors in a capacitor? 

answer: a non-conductive region

question: What is the name given to the area between two conductors in a capacitor? 

answer: the dielectric

question: What net electric charge are capacitors assumed to have? 

answer: no net electric charge

question: What type of charges do conductors hold on their facing surfaces? 

answer: equal and opposite charges

question: What region within a capacitor develops an electric field? 

answer: the dielectric
Title: Capacitor
Context: The current I(t) through any component in an electric circuit is defined as the rate of flow of a charge Q(t) passing through it, but actual charges—electrons—cannot pass through the dielectric layer of a capacitor. Rather, one electron accumulates on the negative plate for each one that leaves the positive plate, resulting in an electron depletion and consequent positive charge on one electrode that is equal and opposite to the accumulated negative charge on the other. Thus the charge on the electrodes is equal to the integral of the current as well as proportional to the voltage, as discussed above. As with any antiderivative, a constant of integration is added to represent the initial voltage V(t0). This is the integral form of the capacitor equation:

question: What is the definition of the current I(t) through any component in an electric circuit? 

answer: the rate of flow of a charge Q(t) passing through it

question: For each electron that departs the positive plate, how many electrons build up on the negative plate? 

answer: one electron accumulates on the negative plate

question: To what is the charge on the electrodes of a capacitor equal to? 

answer: the integral of the current

question: To what is the charge on the electrodes of a capacitor proportional to? 

answer: proportional to the voltage

question: When calculating the integral to determine the charge on the electrodes of a capacitor, what does the constant of integration that must be added represent? 

answer: the initial voltage V(t0)
Title: Capacitor
Context: The simplest model capacitor consists of two thin parallel conductive plates separated by a dielectric with permittivity ε . This model may also be used to make qualitative predictions for other device geometries. The plates are considered to extend uniformly over an area A and a charge density ±ρ = ±Q/A exists on their surface. Assuming that the length and width of the plates are much greater than their separation d, the electric field near the centre of the device will be uniform with the magnitude E = ρ/ε. The voltage is defined as the line integral of the electric field between the plates

question: In an ideal model of a capacitor, what is the value that describes the permittivity of the dielectric? 

answer: permittivity ε

question: What equation describes the charge density for an ideal model of a capacitor? 

answer: ±ρ = ±Q/A

question: In an ideal model of a capacitor, what must be assumed about the size of the plates? 

answer: much greater than their separation d

question: Close to the middle of the capacitor, what equation describes the magnitude of the electric field? 

answer: E = ρ/ε

question: What does the line integral of the electric field between the plates of a capacitor represent? 

answer: The voltage
Title: Capacitor
Context: The maximum energy is a function of dielectric volume, permittivity, and dielectric strength. Changing the plate area and the separation between the plates while maintaining the same volume causes no change of the maximum amount of energy that the capacitor can store, so long as the distance between plates remains much smaller than both the length and width of the plates. In addition, these equations assume that the electric field is entirely concentrated in the dielectric between the plates. In reality there are fringing fields outside the dielectric, for example between the sides of the capacitor plates, which will increase the effective capacitance of the capacitor. This is sometimes called parasitic capacitance. For some simple capacitor geometries this additional capacitance term can be calculated analytically. It becomes negligibly small when the ratios of plate width to separation and length to separation are large.

question: What is a function of the amount of dielectric, the strength of dielectric and its permittivity? 

answer: The maximum energy

question: If the plate area and separation distance are altered while keeping the amount of dielectric the same, what effect is had on the maximum energy of the capacitor?  

answer: no change of the maximum amount of energy

question: In a realistic model of a capacitor, where else besides between the dielectric between the conductors might an electric field be found? 

answer: fringing fields outside the dielectric

question: When an electric field exists between the sides of the plates as well as in within the dielectric, what effect is had on the effective capacitance of the capacitor? 

answer: will increase the effective capacitance

question: When the ratios of plate length and width to separation distance are large, what size is the parasitic capacitance? 

answer: negligibly small
Title: Capacitor
Context:  Capacitors deviate from the ideal capacitor equation in a number of ways. Some of these, such as leakage current and parasitic effects are linear, or can be assumed to be linear, and can be dealt with by adding virtual components to the equivalent circuit of the capacitor. The usual methods of network analysis can then be applied. In other cases, such as with breakdown voltage, the effect is non-linear and normal (i.e., linear) network analysis cannot be used, the effect must be dealt with separately. There is yet another group, which may be linear but invalidate the assumption in the analysis that capacitance is a constant. Such an example is temperature dependence. Finally, combined parasitic effects such as inherent inductance, resistance, or dielectric losses can exhibit non-uniform behavior at variable frequencies of operation.

question: What characteristic can leakage current and parasitic effects be assumed to have in the equation for a realistic capacitor? 

answer: can be assumed to be linear

question: What sort of components can be added to the equivalent circuit of a capacitor in order to deal with leakage current and parasitic effects? 

answer: virtual components

question: Upon dealing with leakage current and parasitic effects in a realistic model of a capacitor, what sort of methods can then be applied? 

answer: The usual methods of network analysis

question: What sort of analysis cannot be used in cases of voltage breakdown in modelling a capacitor? 

answer: normal (i.e., linear) network analysis cannot be used

question: What causes the assumption of constant capacitance to fail even if the effect is linear in nature? 

answer: temperature dependence
Title: Capacitor
Context: For air dielectric capacitors the breakdown field strength is of the order 2 to 5 MV/m; for mica the breakdown is 100 to 300 MV/m; for oil, 15 to 25 MV/m; it can be much less when other materials are used for the dielectric. The dielectric is used in very thin layers and so absolute breakdown voltage of capacitors is limited. Typical ratings for capacitors used for general electronics applications range from a few volts to 1 kV. As the voltage increases, the dielectric must be thicker, making high-voltage capacitors larger per capacitance than those rated for lower voltages. The breakdown voltage is critically affected by factors such as the geometry of the capacitor conductive parts; sharp edges or points increase the electric field strength at that point and can lead to a local breakdown. Once this starts to happen, the breakdown quickly tracks through the dielectric until it reaches the opposite plate, leaving carbon behind and causing a short (or relatively low resistance) circuit. The results can be explosive as the short in the capacitor draws current from the surrounding circuitry and dissipates the energy.

question: What order is the breakdown field strength for air dielectric capacitors of? 

answer: of the order 2 to 5 MV/m

question: Of what order is the breakdown field strength for mica dielectric capacitors? 

answer: 100 to 300 MV/m

question: In what way is the dielectric used in order to cause the absolute breakdown voltage of capacitors to be limited? 

answer: The dielectric is used in very thin layers

question: What is one factor that critically affects the breakdown voltage of the capacitor? 

answer: the geometry of the capacitor conductive parts

question: What is the difference in the physical attributes of the dielectric used in high voltage capacitors compared to low voltage capacitors? 

answer: the dielectric must be thicker
Title: Capacitor
Context: Ripple current is the AC component of an applied source (often a switched-mode power supply) whose frequency may be constant or varying. Ripple current causes heat to be generated within the capacitor due to the dielectric losses caused by the changing field strength together with the current flow across the slightly resistive supply lines or the electrolyte in the capacitor. The equivalent series resistance (ESR) is the amount of internal series resistance one would add to a perfect capacitor to model this. Some types of capacitors, primarily tantalum and aluminum electrolytic capacitors, as well as some film capacitors have a specified rating value for maximum ripple current.

question: What name is given to the AC component of an applied source having either constant or alternating frequency? 

answer: Ripple current

question: What is one cause of dielectric losses in a capacitor? 

answer: changing field strength

question: What is another cause of dielectric losses in a capacitor? 

answer: current flow across the slightly resistive supply lines or the electrolyte

question: What is the name given to the amount of internal series resistance needed to add to an ideal capacitor model in order to represent the heat generated by dielectric losses? 

answer: equivalent series resistance (ESR)

question: What is one type of capacitor that has a specified rating value for maximum ripple current? 

answer: aluminum electrolytic capacitors
Title: Capacitor
Context: The capacitance of certain capacitors decreases as the component ages. In ceramic capacitors, this is caused by degradation of the dielectric. The type of dielectric, ambient operating and storage temperatures are the most significant aging factors, while the operating voltage has a smaller effect. The aging process may be reversed by heating the component above the Curie point. Aging is fastest near the beginning of life of the component, and the device stabilizes over time. Electrolytic capacitors age as the electrolyte evaporates. In contrast with ceramic capacitors, this occurs towards the end of life of the component.

question: What value of some capacitors decreases with age? 

answer: The capacitance

question: What causes the decrease of capacitance in ceramic capacitors as they age? 

answer: degradation of the dielectric

question: What is one of the most important aging factors in capacitors? 

answer: The type of dielectric

question: What is another important factor which governs how a capacitor ages? 

answer: ambient operating and storage temperatures

question: At what point can the aging effect of a capacitor be reversed if the component is heated beyond? 

answer: the Curie point
Title: Capacitor
Context: Capacitors, especially ceramic capacitors, and older designs such as paper capacitors, can absorb sound waves resulting in a microphonic effect. Vibration moves the plates, causing the capacitance to vary, in turn inducing AC current. Some dielectrics also generate piezoelectricity. The resulting interference is especially problematic in audio applications, potentially causing feedback or unintended recording. In the reverse microphonic effect, the varying electric field between the capacitor plates exerts a physical force, moving them as a speaker. This can generate audible sound, but drains energy and stresses the dielectric and the electrolyte, if any.

question: What is the effect called when capacitors absorb sound waves? 

answer: microphonic effect

question: What value of a capacitor is varied when vibration moves the conducting plates?  

answer: the capacitance

question: What sort of current is induced when the capacitance of a capacitor is altered? 

answer: AC current

question: In what type of applications is piezeoelectricity especially problematic? 

answer: audio applications

question: What is it called when a changing electric field existing between the conductive plates of a capacitor physically moves them? 

answer: the reverse microphonic effect
Title: Capacitor
Context: In DC circuits and pulsed circuits, current and voltage reversal are affected by the damping of the system. Voltage reversal is encountered in RLC circuits that are under-damped. The current and voltage reverse direction, forming a harmonic oscillator between the inductance and capacitance. The current and voltage will tend to oscillate and may reverse direction several times, with each peak being lower than the previous, until the system reaches an equilibrium. This is often referred to as ringing. In comparison, critically damped or over-damped systems usually do not experience a voltage reversal. Reversal is also encountered in AC circuits, where the peak current will be equal in each direction.

question: What is one type of circuit in which voltage and current reversal are affected by damping? 

answer: DC circuits

question: What is another type of circuit in which voltage and current reversal are affected by damping? 

answer: pulsed circuits

question: Under what condition does voltage reversal occur in RLC circuits? 

answer: under-damped

question: What is formed between the inductance and the capacitance when the current and the voltage switch direction? 

answer: a harmonic oscillator

question: When a system is over-damped, what does it typically not experience? 

answer: a voltage reversal
Title: Capacitor
Context: For maximum life, capacitors usually need to be able to handle the maximum amount of reversal that a system will experience. An AC circuit will experience 100% voltage reversal, while under-damped DC circuits will experience less than 100%. Reversal creates excess electric fields in the dielectric, causes excess heating of both the dielectric and the conductors, and can dramatically shorten the life expectancy of the capacitor. Reversal ratings will often affect the design considerations for the capacitor, from the choice of dielectric materials and voltage ratings to the types of internal connections used.

question: What percentage of voltage reversal does an AC circuit experience? 

answer: 100% voltage reversal

question: What does voltage reversal create in the dielectric of a capacitor? 

answer: excess electric fields

question: What percentage of voltage reversal will an under damped DC circuit experience? 

answer: less than 100%

question: What does excess electric field present in the dielectric lead to? 

answer: heating of both the dielectric and the conductors

question: When designing a capacitor, what is an important rating to consider? 

answer: Reversal ratings
Title: Capacitor
Context: Capacitors made with any type of dielectric material will show some level of "dielectric absorption" or "soakage". On discharging a capacitor and disconnecting it, after a short time it may develop a voltage due to hysteresis in the dielectric. This effect can be objectionable in applications such as precision sample and hold circuits or timing circuits. The level of absorption depends on many factors, from design considerations to charging time, since the absorption is a time-dependent process. However, the primary factor is the type of dielectric material. Capacitors such as tantalum electrolytic or polysulfone film exhibit very high absorption, while polystyrene or Teflon allow very small levels of absorption. In some capacitors where dangerous voltages and energies exist, such as in flashtubes, television sets, and defibrillators, the dielectric absorption can recharge the capacitor to hazardous voltages after it has been shorted or discharged. Any capacitor containing over 10 joules of energy is generally considered hazardous, while 50 joules or higher is potentially lethal. A capacitor may regain anywhere from 0.01 to 20% of its original charge over a period of several minutes, allowing a seemingly safe capacitor to become surprisingly dangerous.

question: After discharging and disconnecting a capacitor, what causes it to develop a voltage? 

answer: hysteresis in the dielectric

question: What does the process of dielectric absorption in a capacitor depend on? 

answer: time-dependent

question: What level of dielectric absorption would a tantalum electrolytic capacitor display?  

answer: very high absorption

question: What level of dielectric absorption would a Teflon capacitor exhibit? 

answer: very small levels of absorption

question: What amount of energy must a capacitor contain in order to be generally considered dangerous?  

answer: over 10 joules of energy