CAPACITORS. IF A CAPACITORS JOB IS TO STORE ELECTRICAL CHARGE, WHERE WOULD THEY BE USEFUL?

Slides:

Advertisements

Similar presentations

CAPACITORS SLIDES BY: ZIL E HUMA. OBJECTIVES CHARGING OF THE CAPACITORS DISCHARGING OF THE CAPACITORS DIELECTRIC MATERIALS FACTORS EFFECTING THE VALUES.

Advertisements

Capacitors1 THE NATURE OF CAPACITANCE All passive components have three electrical properties Resistance, capacitance and inductance Capacitance is a measure.

Chapter 23 Capacitance.

Application – Xerographic Copiers

17-7 Capacitance A device that stores electric charge Two plates that are separated by an insulator Used in electronic circuits Store charge that can later.

Capacitance. Device that stores electric charge. Construction: A capacitor is two conducting plates separated by a finite distance Typically separated.

Capacitors insulating dielectric Capacitors store charge. They have two metal plates where charge is stored, separated by an insulating dielectric. To.

Objectives: 1. Define and calculate the capacitance of a capacitor. 2. Describe the factors affecting the capacitance of the capacitor. 3. Calculate the.

1 Capacitance and Dielectrics Chapter 27 Physics chapter 27.

Capacitance Physics Department, New York City College of Technology.

ECE 201 Circuit Theory I1 Capacitance Capacitance occurs whenever electrical conductors are separated by a dielectric, or insulating material. Applying.

Capacitance and Dielectrics

Capacitors in a Basic Circuit

IEEE’s Hands on Practical Electronics (HOPE)

Storey: Electrical & Electronic Systems © Pearson Education Limited 2004 OHT 13.1 Capacitance and Electric Fields  Introduction  Capacitors and Capacitance.

Chapter 18 – Electric Potential and Capacitance Section 1 Electric Potential Energy.

Chapter 24 Capacitance, Dielectrics, Electric Energy Storage

4.4 Fields Capacitance Breithaupt pages 94 to 101 September 28 th, 2010.

Engineering Science EAB_S_127 Electricity Chapter 4.

Edexcel A2 Physics Unit 4 : Chapter 2.2: Capacitance Prepared By: Shakil Raiman.

Electricity Foundations of Physics. Electricity The movement of charge from one place to another Requires energy to move the charge Also requires conductors.

Energy Storage Devices Prepared By : Shingala Nital ( ) Paghdal Radhika ( ) Bopaliya Mamta ( ) Guided By : Prof. Tank.

 Devices that can store electric charge are called capacitors.  Capacitors consist of 2 conducting plates separated by a small distance containing an.

Book Reference : Pages To understand what a capacitor is 2.To understand their applications 3.To understand how we define capacitance.

Electrical Energy and Capacitance. Electrical Potential Energy Potential energy associated with the electrical force between two charges Form of mechanical.

Capacitors. A capacitor is a device which is used to store electrical charge ( a surprisingly useful thing to do in circuits!). Effectively, any capacitor.

1 CAPACITORS 2 BASIC CONSTRUCTION INSULATOR CONDUCTOR + - TWO OPPOSITELY CHARGED CONDUCTORS SEPARATED BY AN INSULATOR - WHICH MAY BE AIR The Parallel.

Capacitance, Capacitors and Circuits. Start with a review The capacitance C is defined as To calculate the capacitance, one starts by introduce Q to the.

Capacitors. What is a capacitor? Electronic component Two conducting surfaces separated by an insulating material Stores charge Uses –Time delays –Filters.

-Combinations of Capacitors -Energy Stored in a Charged Capacitor AP Physics C Mrs. Coyle.

Electric Energy and Capacitance

Electrical Circuits. Electrical Circuit Closed path through which charge can flow A Circuit needs: 1.Source of energy (voltage) 2.Conductive path for.

Capacitance PHY 2049 Chapter 25 Chapter 25 Capacitance In this chapter we will cover the following topics: -Capacitance C of a system of two isolated.

111/16/2015 ELECTRICITY AND MAGNETISM Phy 220 Chapter 4: Capacitors.

CAPACITORS NCEA Level 3 Physics CAPACITORS Electric field strength Capacitors Capacitance & Charge Energy in capacitors Capacitors in series and.

CAPACITORS. A capacitor is a device used to “store” electric charge. It can store energy and release it very quickly!!

Chapter 16 Electrical Energy AndCapacitance. General Physics Review - Electric Potential for a system of point charges.

Capacitance Physics Montwood High School R. Casao.

Chapter 25 Lecture 20: Capacitor and Capacitance.

Today’s agenda: Capacitance. You must be able to apply the equation C=Q/V. Capacitors: parallel plate, cylindrical, spherical. You must be able to calculate.

Electric Potential: Charged Conductor

Power Supply (so big you never notice the level going down) Tap Capacitor V Area represents capacitance, C Volume represents charge, Q Capacitor Model.

12/4/2016 Advanced Physics Capacitance  Chapter 25 – Problems 1, 3, 8, (17), 19, (33), 39, 40 & 49.

The Capacitor A capacitor is an electronic device which can store charge. The symbol for a capacitor is: Capacitance is measured in Farads (F) or, more.

Capacitors The capacitor is an element that continuously stores charge (energy), for later use over a period of time! In its simplest form, a capacitor.

Capacitors Separating charge and storing energy..

Capacitance What do you expect to happen when you close the switch? Actually nothing doesn’t happen - as you well know, one wire “becomes positive and.

Review Question Describe what happens to the lightbulb after the switch is closed. Assume that the capacitor has large capacitance and is initially uncharged,

Capacitance. Device that stores electric charge. Construction: A capacitor is two conducting plates separated by a finite distance Typically separated.

Objectives: 1. Define and calculate the capacitance of a capacitor. 2. Describe the factors affecting the capacitance of the capacitor. 3. Calculate the.

Objectives: 1. Define and calculate the capacitance of a capacitor. 2. Describe the factors affecting the capacitance of the capacitor. 3. Calculate the.

Review: Kirchoff’s Rules Activity 13C Achieved level: Qn. 1; Merit: Qn. 2, 3, 4, 5, 6 Excellence: Qn. 3 d, 6 b) iv. Challenge Problem on paper at the front.

Capacitor Charging and Discharging 18-Jan-08 Mr.NGAN HON SHING.

Capacitor Device that can store electric charge Two conducting objects are placed near one another but not touching Power source charges up the plates,

Capacitors A capacitor is a device that has the ability “capacity” to store electric charge and energy.

Capacitors. What is a capacitor? Electronic component Two conducting surfaces separated by an insulating material Stores charge Uses –Time delays –Filters.

Capacitance Capacitance occurs whenever electrical conductors are separated by a dielectric, or insulating material. Applying a voltage to the conductors.

Capacitors Construction and charging and discharging.

Course work Next week we are doing another PRACTICE course work

Capacitors: parallel plate, cylindrical, spherical.

Phys102 Lecture 7/8 Capacitors

Potential Difference and Capacitance

Electric Potential: Charged Conductor

FIGURE 12-1 A Leyden jar can be used to store an electrical charge.

FIGURE 12-1 A Leyden jar can be used to store an electrical charge.

Capacitance and Capacitors

Capacitor Is a device that stores energy by maintaining a separation between positive and negative charge. Compare stored energy / charge to a bucket.

Presentation transcript:

CAPACITORS

IF A CAPACITORS JOB IS TO STORE ELECTRICAL CHARGE, WHERE WOULD THEY BE USEFUL?

USES Found in radios/tv's/computers Control timings in car and burglar alarms Camera flashes Tumble drier - to get the drum to rotate All devices where a sudden burst of energy is required Lasers used in nuclear fusion

CAPACITORS A capacitor is an electrical device which stores charge. Capacitance,C is defined as the amount of charge stored per unit p.d. C = Q / V Capacitance is measured in the unit of FARAD, F. 1F = 1C per V One Farad is large so capacitance is normally quoted in micro farads, nano farads or pico farads.

CIRCUIT SYMBOLS

HOW DO THEY WORK? A capacitor consists of two conducting plates. One connected to positive and the other to negative. These plates become 'charged' The amount of energy stored by the capacitor depends on how much charge is moved to the plates. The plates are separated by an insulating material called the DIELECTRIC. The plates need to have a large area and to achieve this capacitors consist of two long stripes of metal, separated by the dielectric and rolled up like a Swiss roll.

TO CHARGE To charge,connect a capacitor to a battery - electrons flow from the negative terminal to the negative plate. At the same time electrons are repelled away from the positive plate to the positive terminal of the battery. A negative charge builds up on the the negative plate and a positive charge on the positive plate - this increases the p.d. across the plates. Eventually the build up of charge prevents any more charge arriving and the movement of the electrons stops.

TO DISCHARGE To discharge, remove the battery and reconnect the capacitor to the circuit - the electrons on the negative plate are driven around the circuit to neutralise the charge on the opposite plate. The charge on both the plates falls. Therefore the p.d. across them decreases. The capacitor is 'discharged' when there is no more charge left on the plates (no current).

EXPONENTIAL DISCHARGE The time taken to charge/discharge depends on the capacitance of the capacitor, C and the resistance, R of the circuit (which affects the current) When a capacitor discharges, the amount of charge left on the plate falls exponentially with time. As C=Q/V, voltage and current also change exponentially with time.

COMBINED CAPACITANCE Two or more capacitors in parallel have the same p.d. across each one (as each can store the same charge) In parallel Ct = C1 + C2 +.. Two or more capacitor in series share the p.d across them (each capacitor stores some of the charge) In series 1/Ct = 1/C1 + 1/C2 +..

ENERGY STORED BY A CAPACITOR In a capacitor, electrical energy provided by the battery is stored by the capacitor Work is done removing charge from one plate and depositing on the other plate. The energy stored by the capacitor is equal to the work done by the battery. From the area under the graph: W =1/2 QV

OTHER ENERGY EQUATIONS Using W = 1/2 QV and C = Q/V, come up with other energy stored/ work done equations.

TIME CONSTANT The time constant of a capacitor tells us how long it takes for a capacitor to discharge The time constant (tau) is the time it takes for the p.d. to fall to 1/e of it's original value (or 37%) Time constant = capacitance x resistance Why is the unit of time constant, seconds?

EXPONENTIAL EQUATIONS As stated earlier - charge, voltage and current on a capacitor all decay exponentially with time. Equations can be used to calculate the charge, voltage or current left on a capacitor after time t.