# Looking at Capacitors

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Module 2 AC Theory Looking at What you'll learn in Module 2: In section 2.1 Common capacitor types and their uses. Basic Circuit Symbols for. In section 2.2 Charge & Discharge How capacitors work. What is charge? Charge and discharge in a DC circuit In section 2.3 Capacitance What is capacitance? Dielectric. Permittivity. Dielectric strength and maximum working voltage. Calculating the charge on a capacitor. In section 2.4 in Circuits Solving capacitor circuit calculations. in series. in parallel. In section 2.5 Capacitor Quiz Capacitor Quiz AC THEORY MODULE 02.PDF 1 E. COATES

2 Module 2 Introduction to are one of the most useful components in electronics, and after resistors are the most numerous components in circuits. This module introduces diffent types of capacitor and describes their basic operation. Later modules look at how capacitors are used in AC circuits where, together with inductors, they perform an important job in many circuits. This is module 2 of 14 modules. In this module what you will learn is listed in the grey panel. It tells you "What you should know..." as a result of studying the complete module. Each module is divided into several smaller sections and you can check your learning with the "Module Quiz" at the end of the module. Study each section (numbered 2.1, 2.2 etc) in order, and use the quiz questions to help check your understanding. If you would like a PRINT version of other modules, go to the AC Theory section of click the PDF icon in the left column on the appropriate module, to download your copy. AC THEORY MODULE 02.PDF 2 E. COATES

3 Module 2.1 (and inductors) have the ability to store electrical energy, inductors store energy as a magnetic field around the component, but the capacitor stores electrical energy directly, as an ELECTROSTATIC FIELD created between two metal "plates". Fig Basic Circuit Symbols for Fig shows the UK and US circuit symbols for a variety of capacitor types. A basic fixed value type of capacitor consists of two plates made from metallic foil, separated by an insulator. This may be made from a choice of different insulating materials, having good DIELECTRIC properties. Some basic types of capacitor construction are shown in fig 2.1.2a. Have Many Uses. have many uses in electronic circuits. Each purpose uses one or more of the features described in this module. Fig shows a variety of capacitors. Typical uses would include: Fig AC THEORY MODULE 02.PDF 3 E. COATES

4 Capacitor types illustrated on page 3: High Voltage Electrolytic used in power supplies. Axial Electrolytic; lower voltage smaller size for general purpose where large capacitance values are needed. High Voltage disk ceramic; small size and capacitance value, excellent tolerance characteristics. Metalised Polypropylene; small size for values up to around 2µF good reliability. Sub miniature Multi layer ceramic chip (surface mount) capacitor. Relatively high capacitance for size achieved by multiple layers, effectively several capacitors in parallel. Fig a Construction Fixed Value The construction of non polarized capacitors follows the same pattern over many types. Variations consist of the area of the plates and type of dielectric material used for a given capacitance; ideally the dielectric will be the thinnest material, with the best permitivity, that will also withstand the voltage required. Each of the basic types shown in Fig 2.1.2a will be coated with an insulating layer (often an epoxy resin). Electrolytic The construction of electrolytic capacitors is similar in some ways to a rolled foil capacitor. Except that the layers between the foil are now two very thin layers of paper, one that forms an insulator separating the rolled pairs of layers and the other, a layer of tissue between the foil plates, soaked in an electrolyte that makes the tissue conductive! It would seem from the previous paragraph that the soaked tissue places a short circuit between the plates. But the real dielectric layer is created after construction is complete, in a process called "Forming". A current is passed through the capacitor, and the action of the electrolyte causes a very thin layer of aluminium oxide to build up on the positive plate. It is this layer that is used as the insulating dielectric. The capacitor therefore has a very thin and efficient dielectric, giving capacitance values many hundreds times greater than is possible with a conventional plastic film capacitor of a similar physical size. AC THEORY MODULE 02.PDF 4 E. COATES

5 The down side with this process is that the capacitor is polarised and must not have reversed polarity voltages applied. If this occurs the insulating oxide layer is stripped away again and the capacitor may pass a large current. As this occurs in a sealed container, the "liquid" electrolyte quickly boils and expands rapidly. This can lead to an explosion within seconds! NEVER connect an electrolytic capacitor the wrong way round! Variable capacitors Fig The variable capacitors shown in fig are used as tuning capacitors in AM radios, although they have largely been replaced by "Varicap" (variable capacitance) diodes, but they can still be found in circuit diagrams and supplier's catalogues for replacement purposes. Tuning capacitors have very small values of typically a few pf to a few tens of pf. Large air dielectric types, like the animated one on the left have been superseded by miniature types as shown top right (front and back to show the tiny trimmer capacitors accessed through holes in the rear of the case). Trimmer capacitors Small trimmer capacitors, adjustable with special trimming tools (DON T use a screwdriver!) by technicians rather than the equipment user are available in a variety of very small designs. They work in a similar way to the larger variables, with tiny rotating plates and typically PVC film dielectric layers between. Their capacitance is only a few pico farads and they are often used in conjunction with larger variable capacitors (and even fitted inside the case of tuning capacitors) to improve accuracy. AC THEORY MODULE 02.PDF 5 E. COATES

6 Fig Variable and Preset Capacitor Symbols Symbols for variable capacitors are given in fig Variable capacitors are often available as GANGED components. Usually two variable capacitors are adjusted by a single control spindle. The arrow symbol indicates a variable capacitor (adjustable by the equipment user, and the T shaped diagonal indicates a preset capacitor, for technician adjustment only. The dotted line connecting a pair of capacitors indicates that they are ganged. AC THEORY MODULE 02.PDF 6 E. COATES

7 Module 2.2 Charge & Discharge How a capacitor gets its charge Fig Charge and Discharge When a capacitor is connected in a DC circuit as in Fig 2.2.1a, a large current will flow, but only for a short time. When the switch is closed to contact A and electrons begin to flow from the negative battery terminal, and appear to be flowing around the circuit. Of course they can't because the capacitor has a layer of insulation between its plates, so electrons from the negative battery terminal crowd onto the right hand plate of the capacitor creating an increasingly strong negative charge. The very thin insulating (dielectric) layer between the plates is able to efficiently transfer this negative charge from the electrons, and this charge repels the same number of electrons from the left hand plate of the capacitor. These displaced electrons from the left hand plate are attracted towards the positive terminal of the battery, giving the impression of current flowing around the complete circuit. Fig Fig Why the current falls Full charge After a short time (Fig 2.2.1b) however, a large number of electrons have gathered on the right hand plate of the capacitor, creating a growing negative charge, making it increasingly difficult for electrons flowing from the negative battery terminal to reach the capacitor plate because of the repulsion from the growing number of negative electrons gathered there. Eventually (Fig 2.2.1c) the repulsion from the electrons on the capacitor's right hand plate is approximately equal to the force from the negative battery terminal and current ceases. Once the battery and capacitor voltages are equal we can say that the capacitor has reached its maximum charge. If the battery is now disconnected by opening the switch, the capacitor will remain in a charged state, with a voltage equal to the battery voltage, and provided that no current flows, it should remain charged indefinitely. In practice a very small leakage current will flow across the dielectric, and the capacitor will eventually discharge. This process however can take seconds, hours, days, weeks or months, depending on individual circumstances. Fig Fig Fig 2.2.1e Discharging the capacitor Suppose that with the capacitor fully charged, the switch is now closed in position B. (Fig 2.2.1d) the circuit is complete once more, but this time consisting of a resistor and capacitor. Electrons will now flow around the circuit via the resistor as the charge on capacitor acts as the source of current The charge on the capacitor will be depleted as the current flows. (Fig 2.2.1e) The rate at which the capacitor voltage reduces towards zero will depend on the amount of current flowing, and thus on the value of the resistance in the circuit, in Fig this resistance is represented by the lamp. AC THEORY MODULE 02.PDF 7 E. COATES

8 The indicator lamp Using a lamp as a load resistance connected in series with the capacitor gives a useful indication of the operation of the circuit. Initially, as the capacitor begins to charge, the large current makes the lamp glow brightly. As the current reduces due to the build up of charge on the capacitor, the lamp dims and goes out once the capacitor is fully charged. When the switch is in position B and the charged capacitor begins to discharge, the lamp glows brightly once more, dimming and going out as the current falls towards zero due to the diminishing charge on the capacitor. Notice that during discharge, the current is flowing through the lamp in the opposite direction to the flow during the charging period. AC THEORY MODULE 02.PDF 8 E. COATES

9 Module 2.3 Capacitance The amount of energy a capacitor can store depends on the value or CAPACITANCE of the capacitor. Capacitance (symbol C) is measured in the basic unit of the FARAD (symbol F). One Farad is the amount of capacitance that can store 1 Coulomb (6.24 x electrons) when it is charged to a voltage of 1 volt. The Farad is much too large a unit for use in electronics however, so we more often find the following sub-units of capacitance more useful. Sub unit Abbreviation Standard notation micro Farads µf x 10-6 nano Farads nf x 10-9 pico Farads pf x Remember however, that when working out problems involving capacitance, the formulae we use need the values in the basic units of Farads, Volts etc. Therefore when entering a value of 0.47nF into a formula (and your calculator) you should enter it as; 0.47 x 10-9 Farad Capacitance depends on four things; The Dielectric Permittivity 1.The area of the plates 2.The distance between the plates 3.The type of dielectric material 4.Temperature Of these four, temperature has the least effect in most capacitors. The value of most capacitors is fairly stable over a "normal" range of temperatures. Capacitor values may be fixed or variable. Most variable capacitors have a very small value a few tens or hundreds of pf). The value is varied by either: Changing the area of the plates. Changing the thickness of the dielectric. Capacitance (C) is DIRECTLY PROPORTIONAL TO THE AREA OF THE TWO PLATES that directly overlap, the greater the overlapping area, the greater the capacitance. Capacitance is INVERSELY PROPORTIONAL TO THE DISTANCE BETWEEN THE PLATES. i.e. if the plates move apart, the capacitance reduces. The electrons on one plate of the capacitor affect the electrons on the other plate by causing the orbits of the electrons within the dielectric material (the insulating layer between the plates) to distort. The amount of distortion depends on the nature of the dielectric material and this is measured by the permittivity of the material. Permittivity is quoted for any particular material as RELATIVE PERMITTIVITY, which is a measure of how efficient a dielectric material is. It is a number without units which indicates how much greater the permittivity of the material is than the permittivity of air (or a vacuum), which is AC THEORY MODULE 02.PDF 9 E. COATES

10 Dielectric Strength given a permittivity of 1 (one). For example, if a dielectric material such as mica has a relative permittivity of 6, this means the capacitor will have a permittivity, and so a capacitance, six times that of one whose dimensions are the same, but whose dielectric is air. Another important aspect of the dielectric is the DIELECTRIC STRENGTH. this indicates the ability of the dielectric to withstand the voltage placed across it when the capacitor is charged. Ideally the dielectric must by as thin as possible, so giving the maximum capacitance for a given size of component. However, the thinner the dielectric layer, the more easily its insulating properties will break down. The dielectric strength therefore governs the maximum working voltage of a capacitor. Maximum Working Voltage (VDCwkg max) Charge on a Capacitor. It is very important when using capacitors that the maximum working voltage indicated by the manufacturer is not exceeded. Otherwise there will be a great danger of a sudden insulation breakdown within the capacitor. As it is likely that a maximum voltage existed across the capacitor at this time (hence the breakdown) large currents will flow with a real risk of fire or explosion in some circuits. The charge (Q) on a capacitor depends on a combination of the above factors, which can be given together as the Capacitance (C) and the voltage applied (V). For a component of a given capacitance, the relationship between voltage and charge is constant. Increasing the applied voltage results in a proportionally increased charge. This relationship can be expressed in the formula; Maths Help Q = CV or C = Q/V or V = Q/C Where V is the voltage applied, in Volts. C is the capacitance in Farads. Q is the quantity of charge in Coulombs. So any of these quantities can be found provided the other two are known. The formulae can easily be re-arranged using a simple triangle similar to the one used for calculating Ohm's Law when carrying out resistor calculations. Want some help with electronics math? Download our helpful booklet from the "Downloads" page of with tips for buying and using a scientific calculator and for sorting out all those electronics values; invaluable help for the questions in our Module Quizzes and the examples in Module 2.4. AC THEORY MODULE 02.PDF 10 E. COATES

11 Module 2.4 in Circuits in series. Like resistors and inductors, capacitors can be connected in series, in parallel or in series-parallel. Placing capacitors in series effectively increases the thickness of the dielectric, and so reduces the total capacitance. Because the total capacitance is inversely proportional to the distance between the plates, the formula we use for capacitors in SERIES is; in parallel. Note that the voltage across each capacitor will be inversely proportional to the capacitance, with the total voltage being shared out between the capacitors, the smallest capacitance having the largest voltage across it and the largest capacitance having the smallest voltage etc. Connecting capacitors in parallel effectively increases the area of the plates, therefore the total capacitance is given by the sum of the individual capacitances. Parallel capacitors all charge to the same voltage. Note that when using these formulae the values must be put into the formula in their BASIC UNITS i.e. FARADS (not µf) Coulombs (not µc) and VOLTS (not mv). Briefly 47nF; (nanofarads) is entered as; 15 EXP -09 and 25mC (millicoulombs) is entered as; 25 EXP -03 etc. This is easiest to do using a scientific calculator. Now try calculating the total capacitance of some series and parallel circuits in the capacitors Quiz. AC THEORY MODULE 02.PDF 11 E. COATES

12 Module 2.5 Capacitor Quiz What you should know. After studying Module 2, you should: Be able to Recognise common capacitor types and circuit symbols Be able to describe charge and discharge in capacitors Be able to describe dielectric strength and capacitance, and relate capacitance to charge. Be able to use appropriate units of capacitance, and to calculate capacitance in series and parallel capacitor networks. Try our quiz, based on the information you can find in Module 2. Check your answers on line at What is the approximate total capacitance of this parallel circuit? a) 320pF b) 147pF c) 3.2nF d) 1.47nF What is the approximate total capacitance of this series circuit? a) 1.6nF b) 576pF c) 14.4pF d) 12pF When might it be necessary to use a 2 µf polyester capacitor rather than a 2 µf electrolytic capacitor? a) When High Voltages are present b) When the capacitor passes AC c) In low temperature conditions d) When small size is the most important factor. When a DC voltage is applied to a capacitor in its uncharged state:- a) The capacitor voltage will be maximum but fall after a short time b) The voltage will gradually rise at the same rate as the applied current c) Maximum current will flow immediately d) Maximum current will flow until the capacitor is fully charged AC THEORY MODULE 02.PDF 12 E. COATES

13 5. Complete the following sentence: As a capacitor charges a) Electrons gather on the negative plate and displace electrons from the positive plate. b) Electrons flow across the dielectric layer until the capacitor is fully charged c) Electrons gather on the positive plate displacing electrons from the negative plate. d) Current only flows through the capacitor for a short time. What type of capacitor does the component symbol (right) represent? a) A preset capacitor b) An electrolytic capacitor c) A variable capacitor d) A ganged capacitor Calculate the value of capacitance needed to store 1 µc of charge at 10V. a) 10 µf b) 1nF c) 100nF d) 10nF If a voltage is applied across the capacitor network shown, which individual capacitor has the largest voltage across it? a) C1 b) C2 c) C3 d) C What is the approximate total capacitance of the network shown? a) 13.05nF b) 1.01uF c) 391pF d) 2.3nF Capacitance is directly proportional to: a) The distance between the plates. b) The area of the plates. c) The dielectric strength. d) The charge multiplied by the applied voltage. AC THEORY MODULE 02.PDF 13 E. COATES

### EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 2 - CAPACITANCE

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 2 - CAPACITANCE 2 Understand the concepts of capacitance and determine capacitance values in DC circuits

### When we do not get specific resistor values we have to either use variable resistors such as

RESISTOR COMBINATIONS When we do not get specific resistor values we have to either use variable resistors such as potentiometers or presets to obtain such precise values. Pots are too expensive to use

### RVRUSA LCC. Capacitance & Capacitors (Bogart, page 285)

Capacitance & Capacitors (Bogart, page 285) Capacitance is a measure of a component s ability to store charge. A capacitor is a device specially designed to have a certain amount of capacitance. This ability

### Episode 126: Capacitance and the equation C =Q/V

Episode 126: Capacitance and the equation C =Q/V Having established that there is charge on each capacitor plate, the next stage is to establish the relationship between charge and potential difference

### Measurement of Capacitance

Measurement of Capacitance Pre-Lab Questions Page Name: Class: Roster Number: Instructor:. A capacitor is used to store. 2. What is the SI unit for capacitance? 3. A capacitor basically consists of two

### Storing And Releasing Charge In A Circuit

Storing And Releasing Charge In A Circuit Topic The characteristics of capacitors Introduction A capacitor is a device that can retain and release an electric charge, and is used in many circuits. There

### CAPACITIVE REACTANCE. We have already discussed the operation of a capacitor in a DC circuit, however let's just go over the main principles again.

Reading 13 Ron Bertrand VK2DQ http://www.radioelectronicschool.com CAPACITOR IN A DC CIRCUIT CAPACITIVE REACTANCE We have already discussed the operation of a capacitor in a DC circuit, however let's just

### Lab 4 - Capacitors & RC Circuits

Lab 4 Capacitors & RC Circuits L41 Name Date Partners Lab 4 Capacitors & RC Circuits OBJECTIVES To define capacitance and to learn to measure it with a digital multimeter. To explore how the capacitance

### Fall 12 PHY 122 Homework Solutions #4

Fall 12 PHY 122 Homework Solutions #4 Chapter 23 Problem 45 Calculate the electric potential due to a tiny dipole whose dipole moment is 4.8 x 10-30 C.m at a point 4.1 x 10-9 m away if this point is (a)

### LAB 4: CAPACITORS AND RC CIRCUITS

1 Name Date Partner(s) OBJECTIVES LAB 4: CAPACITORS AND RC CIRCUITS! To define capacitance and to learn to measure it with a digital multimeter.! To discover how the capacitance of conducting parallel

### Components in Series, Parallel, and Combination

Components in Series, Parallel, and Combination Kirchoff s Laws VOLTAGE LAW: A series circuit of voltages across the various components must add up to be equal to the voltage applied to the circuit. CURRENT

### EE301 Lesson 14 Reading: 10.1-10.4, 10.11-10.12, 11.1-11.4 and 11.11-11.13

CAPACITORS AND INDUCTORS Learning Objectives EE301 Lesson 14 a. Define capacitance and state its symbol and unit of measurement. b. Predict the capacitance of a parallel plate capacitor. c. Analyze how

### Capacitors in Circuits

apacitors in ircuits apacitors store energy in the electric field E field created by the stored charge In circuit apacitor may be absorbing energy Thus causes circuit current to be reduced Effectively

### Pre-Lab 7 Assignment: Capacitors and RC Circuits

Name: Lab Partners: Date: Pre-Lab 7 Assignment: Capacitors and RC Circuits (Due at the beginning of lab) Directions: Read over the Lab Handout and then answer the following questions about the procedures.

### Lab 5 RC Circuits: Charge Changing in Time Observing the way capacitors in RC circuits charge and discharge.

Print Your Name Lab 5 RC Circuits: Charge Changing in Time Observing the way capacitors in RC circuits charge and discharge. Print Your Partners' Names Instructions October 15, 2015October 13, 2015 Read

### AS Systems & Control Study Notes Part 2: Electronic Materials. E.Clarvis Conductors. Materials

Part 1 Learning Objectives Know the properties of Semiconductors. Know the properties and functions of: Resistors s Materials There are three main types of materials used in electronic and electrical systems:

### Chapter 26. Capacitance and Dielectrics

Chapter 26 Capacitance and Dielectrics Capacitors Capacitors are devices that store electric charge Examples where capacitors are used: radio receivers filters in power supplies energy-storing devices

### LCR Series Circuits. AC Theory. Introduction to LCR Series Circuits. Module 9. What you'll learn in Module 9. Module 9 Introduction

Module 9 AC Theory LCR Series Circuits Introduction to LCR Series Circuits What you'll learn in Module 9. Module 9 Introduction Introduction to LCR Series Circuits. Section 9.1 LCR Series Circuits. Amazing

### Experiment 9 ~ RC Circuits

Experiment 9 ~ RC Circuits Objective: This experiment will introduce you to the properties of circuits that contain both resistors AND capacitors. Equipment: 18 volt power supply, two capacitors (8 µf

### OCR (A) specifications: 5.4.7a,b,c,d,e,f,g,h. Chapter 7 Capacitors

OCR (A) specifications: 5.4.7a,b,c,d,e,f,g,h Chapter 7 Capacitors Worksheet Worked examples Practical : Determining the capacitance of a parallel-plate capacitor Practical 2: Determining the capacitance

### People s Physics Book

The Big Idea When current flows through wires and resistors in a circuit as a result of an electric potential, charge does not build up significantly anywhere on the path. Capacitors are devices placed

### UETTDRIS32A Solve electrical problems in remote community network apparatus

UETTDRIS32A Solve electrical problems in remote community network apparatus Release: 1 UETTDRIS32A Solve electrical problems in remote community network apparatus Modification History Not applicable. Unit

### Science AS90191 Describe Aspects of Physics.

Circuits and components Science AS90191 Describe Aspects of Physics. An electric current is the movement of electrons (negatively charged particles). A circuit is made up of components connected together

### CAUTION! A high-quality capacitor can hold a charge for long periods of time.

CAUTION! A high-quality capacitor can hold a charge for long periods of time. To prevent a painful shock, the capacitor must be discharged before its removal. What Is A Capacitor? For HVAC technicians,

### Kirchhoff's Rules and Applying Them

[ Assignment View ] [ Eðlisfræði 2, vor 2007 26. DC Circuits Assignment is due at 2:00am on Wednesday, February 21, 2007 Credit for problems submitted late will decrease to 0% after the deadline has passed.

### 1 of 7 3/23/2010 2:45 PM

1 of 7 3/23/2010 2:45 PM Chapter 30 Homework Due: 8:00am on Tuesday, March 23, 2010 Note: To understand how points are awarded, read your instructor's Grading Policy. [Return to Standard Assignment View]

### Electrical Energy, Potential and Capacitance. AP Physics B

Electrical Energy, Potential and Capacitance AP Physics B Electric Fields and WORK In order to bring two like charges near each other work must be done. In order to separate two opposite charges, work

### DEALING WITH AC MAINS

ARTICLE DEALING WITH AC MAINS D.MOHAN KUMAR One of the major problem that is to be solved in an electronic circuit design is the production of low voltage DC power supply from AC mains to power the circuit.

### Capacitors Lab. In order to investigate electric fields you will need the following equipment. Home-made parallel capacitor with wax paper in between

Capacitors Lab 1 Equipment In order to investigate electric fields you will need the following equipment Home-made parallel capacitor with wax paper in between DC voltage supply Electrometer Variable capacitor

### 9: Capacitors and Inductors

E1.1 Analysis of Circuits (2015-7150) and : 9 1 / 12 A capacitor is formed from two conducting plates separated by a thin insulating layer. If a currentiflows, positive change,q, will accumulate on the

### Concepts and principles of electricity

Unit 5 Uses Concepts and Principles of Electricity Physics Chapter 5 Concepts and principles of electricity Competency Uses concepts and principles of electricity in daily life Competency level 5' 1' Produces

### UNIT 24: CAPACITORS AND RC CIRCUITS Approximate Time Two 100-minute Sessions

Name St.No. - Date(YY/MM/DD) / / Section Group # UNIT 24: CAPACITORS AND RC CIRCUITS Approximate Time Two 100-minute Sessions + + + + - - - - The most universal and significant concept to come out of the

### Power Supplies. 1.0 Power Supply Basics. www.learnabout-electronics.org. Module

Module 1 www.learnabout-electronics.org Power Supplies 1.0 Power Supply Basics What you ll learn in Module 1 Section 1.0 Power Supply Basics. Basic functions of a power supply. Safety aspects of working

### PHYS-2020: General Physics II Course Lecture Notes Section II

PHYS-2020: General Physics II Course Lecture Notes Section II Dr. Donald G. Luttermoser East Tennessee State University Edition 4.0 Abstract These class notes are designed for use of the instructor and

### Name: Lab Partner: Section:

Chapter 6 Capacitors and RC Circuits Name: Lab Partner: Section: 6.1 Purpose The purpose of this experiment is to investigate the physics of capacitors in circuits. The charging and discharging of a capacitor

### physics 111N electric potential and capacitance

physics 111N electric potential and capacitance electric potential energy consider a uniform electric field (e.g. from parallel plates) note the analogy to gravitational force near the surface of the Earth

### Inductive and Capacitive Reactance

Inductive and Capacitive Reactance Course No: E04-005 Credit: 4 PDH A. Bhatia Continuing Education and Development, Inc. 9 Greyridge Farm Court Stony Point, NY 10980 P: (877) 322-5800 F: (877) 322-4774

### CLASS TEST GRADE 11. PHYSICAL SCIENCES: PHYSICS Test 3: Electricity and magnetism

CLASS TEST GRADE 11 PHYSICAL SCIENCES: PHYSICS Test 3: Electricity and magnetism MARKS: 45 TIME: 1 hour INSTRUCTIONS AND INFORMATION 1. Answer ALL the questions. 2. You may use non-programmable calculators.

### Electricity & Electronics 8: Capacitors in Circuits

Electricity & Electronics 8: Capacitors in Circuits Capacitors in Circuits IM This unit considers, in more detail, the charging and discharging of capacitors. It then investigates how capacitors behave

### Experiments on the Basics of Electrostatics (Coulomb s law; Capacitor)

Experiments on the Basics of Electrostatics (Coulomb s law; Capacitor) ZDENĚK ŠABATKA Department of Physics Education, Faculty of Mathematics and Physics, Charles University in Prague The physics textbooks

### Electrical Fundamentals - Reactance and Impedance

PDHonline Course E239 (4 PDH) Electrical Fundamentals - Reactance and Impedance Instructor: A. Bhatia, B.E. 2012 PDH Online PDH Center 5272 Meadow Estates Drive Fairfax, VA 22030-6658 Phone & Fax: 703-988-0088

### Inductors. AC Theory. Module 3

Module 3 AC Theory What you ll learn in Module 3. Section 3.1 Electromagnetic Induction. Magnetic Fields around Conductors. The Solenoid. Section 3.2 Inductance & Back e.m.f. The Unit of Inductance. Factors

### RC Circuits. 1 Introduction. 2 Capacitors

1 RC Circuits Equipment DataStudio with 750 interface, RLC circuit board, 2 voltage sensors (no alligator clips), 2x35 in. leads, 12 in. lead Reading Review operation of DataStudio oscilloscope. Review

### ELECTROSTATICS. Ans: It is a fundamental property of matter which is responsible for all electrical effects

ELECTROSTATICS One Marks Questions with Answers: 1.What is an electric charge? Ans: It is a fundamental property of matter which is responsible for all electrical effects 2. Write the SI unit of charge?

### TOPIC 4 ELECTRIC CIRCUITS

IGCSE Physics 0625 notes Topic 4: Electric Circuits 1 TOPIC 4 ELECTRIC CIRCUITS ELECTRIC CURRENT (I): Current (I) is defined as the rate of flow of electric charge (Q) in an electric conductor. The unit

### What do resistors do?

This Chapter describes fixed value resistors and outlines some of the important uses of resistors in electronic circuits. What do resistors do? Resistors limit current. In a typical application, a resistor

### Resistor-Capacitor (RC) Circuits

Resistor-Capacitor (RC) Circuits Introduction In this second exercise dealing with electrical circuitry, you will work mainly with capacitors, which are devices that are used to store charge for later

### SOUND METER KIT TEACHING RESOURCES. Version 2.0 HOW LOUD WAS THAT NOISE? FIND OUT WITH THIS

TEACHING RESOURCES SCHEMES OF WORK DEVELOPING A SPECIFICATION COMPONENT FACTSHEETS HOW TO SOLDER GUIDE HOW LOUD WAS THAT NOISE? FIND OUT WITH THIS SOUND METER KIT Version 2.0 Index of Sheets TEACHING RESOURCES

### 1. Purpose Experimental verification of an exponential dependency between two physical quantities. Perform numerical evaluations.

Experimental Science P9: Capacitor charge and discharge 1. Purpose Experimental verification of an exponential dependency between two physical quantities. Perform numerical evaluations. 2. Introduction

### Shining a Light. Design & Technology. Year 9. Structure of an electric torch. Shining a Light

Looking at electronic circuits and what is meant by current, voltage, and resistance. Shining a Light Have you ever taken an electric torch to pieces to find out how it works? Look at the diagram below

### Ch 18 Direct Current Circuits. concept #2, 5, 10, 12, 13, 23 Problems #1, 5, 6, 11, 17, 25, 31, 32, 33, 35, 36, 37

Ch 18 Direct Current Circuits concept #2, 5, 10, 12, 13, 23 Problems #1, 5, 6, 11, 17, 25, 31, 32, 33, 35, 36, 37 currents are maintained by a source of emf (battery, generator) Sources of emf act as charge

### Chapter 21 Electric Current and Direct-Current Circuit

Chapter 2 Electric Current and Direct-Current Circuit Outline 2- Electric Current 2-2 Resistance and Ohm s Law 2-3 Energy and Power in Electric Circuit 2-4 Resistance in Series and Parallel 2-5 Kirchhoff

### Class A Amplifier Design

Module 2 Amplifiers Introduction to Amplifier Design What you ll learn in Module 2. Basic design process. Section 2.0 Introduction to Amplifier Design. Section 2.1 DC Conditions. Design a BJT class A common

### Tech Notes - Variable capacitors

A Variable Capacitor is one whose capacitance may be intentionally and repeatedly changed mechanically. Variable capacitors are often used in L/C circuits to set the resonance frequency, for example, to

### Circuit symbol. Each of the cells has a potential difference of 1.5 volts. Figure 1. Use the correct answer from the box to complete the sentence.

Q.(a) Draw one line from each circuit symbol to its correct name. Circuit symbol Name Diode Light-dependent resistor (LDR) Lamp Light-emitting diode (LED) (3) Figure shows three circuits. The resistors

### 1.2 MOSFET (Metal Oxide Semiconductor Field Effect Transistors)

1.1 Introduction 1 1.1 Introduction The field-effect transistor (FET) controls the current between two points but does so differently than the bipolar transistor. The FET operates by the effects of an

### 16 CAPACITORS. Radial electrolytic capacitors. SMD electrolytic capacitors

16 CAPACITORS Radial electrolytic capacitors Nover SMD electrolytic capacitors A range of miniature radial aluminium electrolytic capacitors for mounting directly to PCBs. All types are fully sleeved.

### How do you measure voltage and current in electric circuits? Materials

20A Electricity How do you measure voltage and current in electric circuits? Electricity Investigation 20A We use electricity every day, nearly every minute! In this Investigation you will build circuits

### LAB 5 - CAPACITORS AND RC CIRCUITS(TPL2)

LAB 5 - CAPACITORS AND RC CIRCUITS(TPL2) Objectives To define capacitance. To discover how the charge on a capacitor and the electric current change with time when a charged capacitor is placed in a circuit

### Discharge of a Capacitor

Discharge of a Capacitor THEORY The charge Q on a capacitor s plate is proportional to the potential difference V across the capacitor. We express this with Q = C V (1) where C is a proportionality constant

### The current that flows is determined by the potential difference across the conductor and the resistance of the conductor (Ohm s law): V = IR P = VI

PHYS1000 DC electric circuits 1 Electric circuits Electric current Charge can move freely in a conductor if an electric field is present; the moving charge is an electric current (SI unit is the ampere

### Eðlisfræði 2, vor 2007

[ Assignment View ] [ Pri Eðlisfræði 2, vor 2007 31. Alternating Current Circuits Assignment is due at 2:00am on Wednesday, March 21, 2007 Credit for problems submitted late will decrease to 0% after the

### Filters & Wave Shaping

Module 8 AC Theory Filters & Wave Shaping Passive Filters & Wave Shaping What you'll learn in Module 8. Module 8 Introduction Recognise passive filters with reference to their response curves. High pass,

### Supercapacitors. Advantages Power density Recycle ability Environmentally friendly Safe Light weight

Supercapacitors Supercapacitors also called ultracapacitors and electric double layer capacitors (EDLC) are capacitors with capacitance values greater than any other capacitor type available today. Capacitance

### Direct versus Alternating Current Things We Can Measure

Phil Sherrod W4PHS Direct versus Alternating Current Things We Can Measure Direct Current (DC) Alternating Current (AC) Voltage Voltage (peak, RMS) Current Current (peak, effective) Power True power, Apparent

### ENGR 1181 Lab 3: Circuits

ENGR 1181 Lab 3: Circuits Lab Procedure Report Guidelines 2 Goal of the Circuits: The Circuits Lab introduces series and parallel circuit which are used by engineers. Students will review this document

### W03 Analysis of DC Circuits. Yrd. Doç. Dr. Aytaç Gören

W03 Analysis of DC Circuits Yrd. Doç. Dr. Aytaç Gören ELK 2018 - Contents W01 Basic Concepts in Electronics W02 AC to DC Conversion W03 Analysis of DC Circuits (self and condenser) W04 Transistors and

### Henry Lin, Department of Electrical and Computer Engineering, California State University, Bakersfield Lecture 3 (Electric Circuits) July 16 th, 2013

Henry Lin, Department of Electrical and Computer Engineering, California State University, Bakersfield Lecture 3 (Electric Circuits) July 16 th, 2013 1 What is an electrical circuit? An electrical network

### Level 2 Physics: Demonstrate understanding of electricity and electromagnetism

Level 2 Physics: Demonstrate understanding of electricity and electromagnetism Static Electricity: Uniform electric field, electric field strength, force on a charge in an electric field, electric potential

### Electric Field Mapping Lab 3. Precautions

HB 09-25-07 Electric Field Mapping Lab 3 1 Electric Field Mapping Lab 3 Equipment mapping board, U-probe, resistive boards, templates, dc voltmeter (431B), 4 long leads, 16 V dc for wall strip Reading

### Position Sensors MicroSense, LLC

Understanding Capacitive Position Sensors 2011 MicroSense, LLC Table of Contents 1. Introduction to Capacitive Sensors... 3 1.1 Characteristics of Capacitive Sensors... 3 1.1.1 Non Contact... 3 1.1.2 High

### Capacitance, Resistance, DC Circuits

This test covers capacitance, electrical current, resistance, emf, electrical power, Ohm s Law, Kirchhoff s Rules, and RC Circuits, with some problems requiring a knowledge of basic calculus. Part I. Multiple

### DVD-8C Print Reading For Electronics Assembly

DVD-8C Print Reading For Electronics Assembly Below is a copy of the narration for DVD-8C. The contents for this script were developed by a review group of industry experts and were based on the best available

### Application Guide Film Capacitors

Capacitance Change vs. Temperature Insulation Resistance vs. Temperature Polyester Typical Characteristics at 1 khz % Capacitance Change % Capacitance Change Polypropylene Typical Characteristics at 1

### BASIC ELECTRONICS PROF. T.S. NATARAJAN DEPT OF PHYSICS IIT MADRAS LECTURE-4 SOME USEFUL LAWS IN BASIC ELECTRONICS

BASIC ELECTRONICS PROF. T.S. NATARAJAN DEPT OF PHYSICS IIT MADRAS LECTURE-4 SOME USEFUL LAWS IN BASIC ELECTRONICS Hello everybody! In a series of lecture on basic electronics, learning by doing, we now

### Fig A Complex Circuit The Raspberry Pi

Module 1 www.learnabout-electronics.org Circuits & Resistors Conductors & Insulators What you ll learn in Module 1 Section 1.1 Conductors & Insulators. Recognise common electrical conductors and their

### Energy in Electrical Systems. Overview

Energy in Electrical Systems Overview How can Potential Energy be stored in electrical systems? Battery Stored as chemical energy then transformed to electrical energy on usage Water behind a dam Water

### Objectives for the standardized exam

III. ELECTRICITY AND MAGNETISM A. Electrostatics 1. Charge and Coulomb s Law a) Students should understand the concept of electric charge, so they can: (1) Describe the types of charge and the attraction

### Capacitors and RC Circuits

Chapter 6 Capacitors and RC Circuits Up until now, we have analyzed circuits that do not change with time. In other words, these circuits have no dynamic elements. When the behavior of all elements is

### Electrical discharge in air e.g. lightning

Static Electricity electron transfer causes static electricity results from an imbalance of charges can occur by induction, friction, and contact You need to describe the direction of motion of charges

### More Concepts. I = dq. Current is the rate of flow of charge around a circuit.

RC Circuits In this presentation, circuits with multiple batteries, resistors and capacitors will be reduced to an equivalent system with a single battery, a single resistor, and a single capacitor. Kirchoff's

### ECE201 Laboratory 1 Basic Electrical Equipment and Ohm s and Kirchhoff s Laws (Created by Prof. Walter Green, Edited by Prof. M. J.

ECE201 Laboratory 1 Basic Electrical Equipment and Ohm s and Kirchhoff s Laws (Created by Prof. Walter Green, Edited by Prof. M. J. Roberts) Objectives The objectives of Laboratory 1 are learn to operate

### EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 1 - D.C. CIRCUITS

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME - D.C. CIRCUITS Be able to use circuit theory to determine voltage, current and resistance in direct

### University Physics 227N/232N Current and Ohm s Law, Resistors, Circuits, and Kirchoff Lab this Friday, Feb 28 So NO QUIZ this Friday!

University Physics 227N/232N Current and Ohm s Law, Resistors, Circuits, and Kirchoff Lab this Friday, Feb 28 So NO QUIZ this Friday! Dr. Todd Satogata (ODU/Jefferson Lab) and Fred Miller satogata@jlab.org

### 1: (ta initials) 2: first name (print) last name (print) brock id (ab13cd) (lab date)

1: (ta initials) 2: first name (print) last name (print) brock id (ab13cd) (lab date) Experiment 1 Capacitance In this Experiment you will learn the relationship between the voltage and charge stored on

### Capacitors. We charge a capacitor by connecting the two plates to a potential difference, such as a battery:

RC Circuits PHYS 1112L Capacitors A capacitor is an electrical component that stores charge. The simplest capacitor is just two charged metal plates separated by a non-conducting material: In the diagram

### How Does it Flow? Electricity, Circuits, and Motors

How Does it Flow? Electricity, Circuits, and Motors Introduction In this lab, we will investigate the behavior of some direct current (DC) electrical circuits. These circuits are the same ones that move

### EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT 4 Understand single-phase alternating current (ac) theory Single phase AC

### ELECTRICAL CIRCUITS. Electrical Circuits

Electrical Circuits A complete path, or circuit, is needed before voltage can cause a current flow through resistances to perform work. There are several types of circuits, but all require the same basic

### Chapter 25: Capacitance

Chapter 25: Capacitance Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone. Albert Einstein 25.1 Introduction Whenever

### CHAPTER 14 -- CAPACITORS QUESTION & PROBLEM SOLUTIONS

Solutions--h 14 (apacitors) HAPTER 14 -- APAITORS QUESTION & PROBLEM SOLUTIONS 141) You have a power supply whose low voltage plate A plate B "ground" terminal is attached to a resistor whose R resistance

### Student Name Instructor Name. High School or Vocational Center Grade. COMPETENCY RECORD FOR ARTICULATION Muskegon Community College Electronics

Student Name Instructor Name High School or Vocational Center Grade COMPETENCY RECORD FOR ARTICULATION Muskegon Community College Electronics Please check below each skill the student has mastered as described,

### Odyssey of the Mind Technology Fair. Simple Electronics

Simple Electronics 1. Terms volts, amps, ohms, watts, positive, negative, AC, DC 2. Matching voltages a. Series vs. parallel 3. Battery capacity 4. Simple electronic circuit light bulb 5. Chose the right

### Lesson 6 Capacitors and Capacitance Lawrence B. Rees 2007. You may make a single copy of this document for personal use without written permission.

Lesson 6 apacitors and apacitance Lawrence B. Rees 7. You may make a single copy of this document for personal use without written permission. 6. Introduction In 745 Pieter van Musschenbroek, while trying

### FM radio kit. Build Instructions. Issue 1.2

FM radio kit Build Instructions Issue 1.2 Build Instructions Before you put any components in the board or pick up the soldering iron, just take a look at the Printed Circuit Board (PCB). The components