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Capacitors

A capacitor is a passive two-terminal electrical component used to store energy electrostatically in an electric field. By contrast, batteries store energy through chemical reactions. The forms of practical capacitors vary widely but all contain at least two electrical conductors separated by an insulator. For example, a common construction consists of metal foils separated by a thin layer of insulating film. Capacitors are widely used as parts of electrical circuits in electrical devices.

Where there is a voltage across the conductors, a static electric field develops across the insulator causing a positive charge to collect on one plate and negative charge on the other plate. Energy Is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value called the capacitance. This is the ratio of the electric charge on each conductor to the potential difference between them. The SI unit of capacitance is a farad. It is equal to one coulomb per volt.

The capacitance is largest when there is a narrow separation between large areas of conductors. Therefore capacitor conductors are often referred to as plates. The insulation between the plates passes a small amount of leakage current and also has an electric field strength limit, the breakdown voltage.

Capacitors are often used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, capacitors smooth the output of the power supply. In resonant circuits, capacitors tune radios to particular frequencies. 

Estimating Power In An 8 Ohm Speaker

Estimate the power developed in the 8 Ω speaker of the circuit of the attached figure for a 1 kHz sinusoidal input signal of 100 mV peak. All capacitors may be assumed to act as a short circuit at the frequency of operation.

Circuit design

I have attached a cmos library for various transistors that pspice does not currently have. I only have access to the Q2N2222 BJT, CD4007 MOS transistor and the 2n7000 transistor and of course all the various resistors and capacitors. If you could please help me design a circuit with the attached specifications using only the pa

Electricity, Magnetism and Waves

See the attached file. 3.) A head is (approximately) a conducting sphere of radius 10 cm. What is the capacitance of the head? What will be the charge on the head if, by means of a Van De Graaf generator, you raise the potential on the head to 100,000 V? What voltage would be required to cause electrostatic break down in ai

Identical Capacitors

Figure attached shows 11 identical capacitors all having capacitance C=70nF and one battery with emf e=150volts. Compute the TOTAL charge that gets stored on all 11 capacitors, NOT the charge that gets stored on each capacitor.

Capacitors in series and parallel

Two condensers are connectedin series across a 100V supply and is found that the potential difference across A is 60V. A condenser of 2mf capacitor is now connected in parallel with A and the potential difference across B rises to 90V. Then the capacitors of A and B are respectively (a) 0.24mf, 0.16mf (b)).16mf,0.24mf (c) 1.6

Connected Capacitors in Parallel

1. A 4mf and an 8.0mf capacitors are connected in parallel across a 25V battery.Find(a)the equivalent capacitance and (b)the total charge stored on the two capacitors. 2. .Two capacitors of charges Q1 and Q2and different capacitance are charged to the same potential; V . They are then connected by a wire. The resulting poten

Amplifier Design: Schematic diagram, Theory of operation, SPICE simulation

The Applied Magnetics Laboratory at the university is developing imaging techniques for monitoring drug delivery to tumors with nano-sized magnetic beads. For this project it has been determined that an amplifier with the following specifications is needed: i) Open circuit voltage gain in |Vo/Vin| of 300 +- 10%. ii) Input re

Capacitors Are Connected in Series, Charge, Potential Difference

Two capacitors are connected in series. Let 3.10 microfarads be the capacitance of first capacitor, 5.50 microfarads the capacitance of the second capacitor, and V= 58.0 Volts the potential difference across the system. A) What is the charge on each of the capacitors? (in micro Coulombs) B) What is the potential differen

Equivalent Capacitance and Charge on the Sphere

Provide answers with complete steps and explanations. 1. Six identical capacitors with capacitance C are connected as shown in the figure in the attachment. a) What is the equivalent capacitance of these six capacitors? b) What is the potential difference between points a and b? 2. The potential at the center of a 3.00-c

Calculate: AM, SSB Reception and Modulation

1. You are asked to build an AM receiver with a 15 micro H inductor which must tune from 500 to 880 kHz. Find the required variable capacitance and the bandwidth at 770 kHz, if the ideal bandwidth at 380 kHz is 10 kHz. 2.A receiver tunes from 20 to 30 MHz using a 10.7 MHz IF. What is the range of the oscillator and image fre

Find the charge and potential difference: Example problem

Please see the file attached for clarity. Capacitors in Combination Problems: 1. A 20- and a 25-pF capacitors are connected in parallel, and a potential difference of 100V is applied to the combination. Find the charge on each capacitor and the potential difference across it. Answer: q1 = 2x10^-9C; q2 = 2.5

Finding charge on each capacitor: Example problem

The battery B supplies 12 V. (a) Find the charge on each capacitor when the switch S1 is closed, and (b) when (later) switch S2 is also closed. Take C1 = 1.0 uF, C2 = 2.0 uF, C3 = 3.0 uF, and C4 = 4.0 uF. See attached image.

Physics: Potential Difference of a Capacitor; Calculate charge on C2

Please solve and explain problem. Part 1: A 0.410 mF (C1) and a 0.630 mF (C2) capacitor are connected in series to a 12.00 V battery. Calculate the potential difference across C1. Part 2: Calculate the charge on C2. Part 3: Now assume that the two capacitors are connected in parallel. Calculate the voltage

Amplifier Circuit and Capacitor Function

Please look at the attached image of an audio amplifier. I know capacitors are storage elements and so forth but how do you know what a capacitor is doing at certain locations? What does terminal 7 capacitor do?

Dielectrics and Infinite Electric Cylinders

1. The space between the spaces of a parallel plate capacitor is filled with two slabs of linear dielectric material. The slabs have different dielectric constants but the same length L, width W and thickness d. (note the area of the top (or bottom) of the capacitor is 2*L*W). Slab 1 has a dielectric constant of e1=2 and slab 2

Physics - Electricity, Magnetism and Waves

Three 3.0 μF capacitors are wired together in-series, and then these three are connected in-parallel with a 5.0 μF capacitor. What is the equivalent capacitance of this arrangement of capacitors?

Capacitors in series and parallel

You have two capacitors, one is 4.0 micro F the other is 2.0 micro F. You also have some wires and a 10.0 V battery. 1. Using the schematic symbols (see attachment), draw a diagram of a circuit with the two capacitors connected in series with the battery. Draw a diagram of a circuit using the same battery and capacitors with

RC Circuit: Potential and Current Variation

In the circuit shown in the figure (see attachment) both capacitors are initially charged to 40.0 V. 1) How long after closing the switch S will the potential across each capacitor be reduced to 10.0 V? 2) What will be the current at that time?

A fuel gauge uses a capacitor to determine the height of the fuel in a tank. It measures the dielectric constant of the combined air and fuel between the capacitor plates as a function of fuel level. To derive an expression for effective dielectric constant etc..

A fuel gauge uses a capacitor to determine the height of the fuel in a tank. The effective dielectric constant K_eff changes from a value of 1 when the tank is empty to a value of K, the dielectric constant of the fuel, when the tank is full. The appropriate electronic circuitry can determine the effective dielectric constant of

Find the Energy Stored in the Capacitor

For the capacitor network shown in the Figure (Intro 1 figure), the potential difference across ab is 12.0 V. Please see the attached page. 1.) Find the energy stored in the 4.80-uF capacitor.

5 questions to understand capacitors in series.

For the capacitor network shown in the figure (please see the attachment), the potential difference across ab is 36 V. 1.) Find the total charge stored in this network. Answer in uF. Express your answer using two significant figures. 2.) Find the charge on each capacitor. Enter your answers numerically separated by a co

Two problems on capacitors

1. Two parallel plates of area 100cm^2 are given charges of equal magnitudes 8.9X10^-7 but opposite signs. The electric field within the dielectric material filling the space between the plates is 1.4X10^6 V/m. (a) Calculate the dielectric constant of the material. (b) Determine the magnitude of the charge induced on each dielec

Calculating Capacitance

The problem states: You have two flat metal plates, each of area 1.00 m^2, with which to construct a parallel-plate capacitor. (a) If the capacitor of the device is to be 1.00 F, what must be the separation between the plates? (b) Could this capacitor actually be constructed? Please review my solution below and correct

A parallel plate capacitor with a nonuniform dielectric

A parallel plate capacitor with a nonuniform dielectric The dielectric of a parallel plate capacitor has a permittivity that varies as ero+ax, where x is the distance from one plate. The area of a plate is A, and their spacing is s. (a) Find the capacitance. (b) Show that, if er varies from ero to 2ero, then c is 1.44 tim

Two capacitors are identical

Two capacitros are identical, except that one is empty and the other is filled with a dielectric (k=4.50). The empty capacitor is connected to a 12.0-V battery. What must be the potential difference across the plates of the capacitor filled with a dielectric such that it stores the same amount of electrical energy as the empty c

Capacitance of Parallel Plate Capacitor

A parallel plate capacitor has a capacitance of 7.0 microFarads when filled with a dielectric. The area of each plate is 1.5 m^2 and the separation between the plates is 1.0 x 10^-5 m. What is the dielectric constant of the dielectric?