BASIC ELECTRONIC COMPONENTS - Robotshop

1 BASIC ELECTRONIC COMPONENTSMODEL ECK-10 Instruction Manualby Arthur F. Seymour MSEEIt is the intention of this course to teach the fundamental operation of basicelectronic COMPONENTS by comparison to drawings of equivalent mechanicalparts. It must be understood that the mechanical circuits would operate muchslower than their ELECTRONIC counterparts and one-to-one correlation can neverbe achieved. The comparisons will, however, give an insight to each of thefundamental ELECTRONIC COMPONENTS used in every ELECTRONIC , 2004, 1994 ElencoTMElectronics, 2004 REV-G 753254 ResistorsCapacitorsCoilsSemiconductorsOt hersTransformers-1-RESISTORSRESISTORS,Wh at do they do?The ELECTRONIC component known as the resistor isbest described as electrical friction.

2 Pretend, for amoment, that electricity travels through hollow pipeslike water. Assume two pipes are filled with waterand one pipe has very rough walls. It would be easyto say that it is more difficult to push the waterthrough the rough-walled pipe than through a pipewith smooth walls. The pipe with rough walls couldbe described as having more resistance tomovement than the smooth in the field of electronics thought electricitywas some type of invisible fluid that could flowthrough certain materials easily, but had difficultyflowing through other materials. In a way they werecorrect since the movement of electrons through amaterial cannot be seen by the human eye, evenwith the best microscopes is asimilarity between the movement of electrons inwires and the movement of water in the pipes.

3 Forexample, if the pressure on one end of a water pipeis increased, the amount of water that will passthrough the pipe will also pressure onthe other end of the pipe will be indirectly related tothe resistance the pipe has to the flow of water. Inother words, the pressure at the other end of thepipe will decrease if the resistance of the 1 shows this flow through materials when a pressure(called voltage in electronics) is placed on one endof the material forcing the electrons to react witheach other until the ones on the other end of thematerial move out. Some materials hold on to theirelectrons more than others making it more difficultfor the electrons to move. These materials have ahigher resistance to the flow of electricity (calledcurrent in electronics) than the ones that allowelectrons to move , earlyexperimenters called the materials insulatorsif theyhad very high resistance to electon flow andconductorsif they had very little resistance toelectron flow.

4 Later materials that offered a mediumamount of resistance were classified a person designs a circuit in electronics, it isoften necessary to limit the amount of electrons orcurrent that will move through that circuit eachsecond. This is similar to the way a faucet limits theamount of water that will enter a glass each would be very difficult to fill a glass withoutbreaking it if the faucet had only two states, wideopen or off. By using the proper value of resistancein an ELECTRONIC circuit designers can limit thepressure placed on a device and thus prevent it frombeing damaged or :The resistor is an electroniccomponent that has electrical friction. This frictionopposes the flow of electrons and thus reduces thevoltage (pressure) placed on other electroniccomponents by restricting the amount of current thatcan pass through 1 Low ResistancePipeHigh ResistancePipe (rough walls)Low PressureHigh PressureThrough SameSize OpeningWater Tank-2-RESISTORSRESISTORS,How are they made?

5 There are many different types of resistors used type is made from are also made to handledifferent amounts of electrical may change their value when voltages areplaced across are called voltagedependent resistors or nonlinearresistors. Mostresistors are designed to change their value whenthe temperature of the resistor changes. Someresistors are also made with a control attached thatallows the user to mechanically change theresistance. These are called variable resistors orpotentiometers. Figure 2 shows physical shapes ofsome different types of first commercial resistors made were formed bywrapping a resistive wire around a non-conductingrod (see Figure 3). The rod was usually made ofsome form of ceramic that had the desired heatproperties since the wires could become quite hotduring caps with leads attached were thenplaced over the ends of the rod making contact tothe resistive wire, usually a nickel chromium value of wirewound resistors remain fairly flatwith increasing temperature, but change greatly withfrequency.

6 It is also difficult to precisely control thevalue of the resistor during construction so theymust be measured and sorted after they are grinding carbon into a fine powder and mixing itwith resin, a material can be made with differentresistive values. Conductive leads are placed oneach end of a cylinder of this material and the unit isthen heated or cured in an oven. The body of theresistor is then painted with an insulating paint toprevent it from shorting if touched by finished resistors are thenmeasured and sorted by value (Figure 4). If theseresistors are overloaded by a circuit, their resistancewill permanently decrease. It is important that thepower rating of the carbon composition resistor isnot 2 Carbon FilmVariableCarbon CompositionTHE WIREWOUND RESISTORF igure 3 THE CARBON COMPOSITION RESISTORC eramic RodWireEnd CapProtective CoatingFigure 4 Insulating PaintCarbon & ResinMixtureConductive Wire-3-RESISTORSCARBON FILM RESISTORSC arbon film resistors are made by depositing a verythin layer of carbon on a ceramic rod.

7 The resistoris then protected by a flameproof jacket since thistype of resistor will burn if overloaded film resistors produce less electrical noisethan carbon composition and their values areconstant at high frequencies. You can substitute acarbon film resistor for most carbon compositionresistors if the power ratings are carefully construction of carbon film resistors requiretemperatures in excess of 1, oxide resistors are also constructed in asimilar manner as the carbon film resistor with theexception that the film is made of tin chloride attemperatures as high as 5, oxideresistors are covered with epoxy or some similarplastic coating. These resistors are more costly thanother types and therefore are only used when circuitconstraints make them film resistors are also made by depositing afilm of metal (usually nickel alloy) onto a resistors are very stable withtemperature and frequency, but cost more than thecarbon film or carbon composition types.

8 In someinstances, these resistors are cased in a ceramictube instead of the usual plastic or epoxy a resistor is constructed so its value can beadjusted, it is called a variable resistor. Figure 6shows the BASIC elements present in all variableresistors. First a resistive material is deposited on anon-conducting base. Next, stationary contacts areconnected to each end of the resistive , a moving contact or wiper is constructed tomove along the resistive material and tap off thedesired resistance. There are many methods forconstructing variable resistors, but they all containthese three BASIC 5 METAL OXIDE RESISTORSMETAL FILM RESISTORSTHE VARIABLE RESISTORF igure 6 Carbon FilmCeramic RodFlameproof JacketLeadsMovableArmWiperContactStation aryContactThin Layerof ResistiveMaterialNon-conductiveBase Material-4-RESISTORSRESISTOR VALUES AND MARKINGSThe unit of measure for resistance is the ohm, whichis represented by the Greek letter improved the process of manufacturingresistors, they were first made and then sorted.

9 Bysorting the values into groups that represented a 5%change in value, (resistor values are 10% apart),certain preferred values became the standard forthe electronics industry. Table 1 shows the standardvalues for 5% are marked by using different coloredrings around their body (see Figure 7). The first ringrepresents the first digit of the resistor s ring represents the second digit of theresistor s value. The third ring tells you the power often to multiply final and fourth ringrepresents the tolerance. For example, gold is for5% resistors and silver for 10% resistors. Thismeans the value of the resistor is guaranteed to bewithin 5% or 10% of the value marked. The colorsin Table 2 are used to represent the numbers from 0to : If the third ring is gold, you multiply the firsttwo digits by and if it is silver, by Thissystem can identify values from as high as91 x 109, or 91,000,000,000W.

10 The amount of powereach resistor can handle is usually proportional tothe size of the resistor. Figure 8 shows the actualsize and power capacity of normal carbon filmresistors, and the symbols used to representresistors on 1 Figure 7 OrangeRedVioletGold27 X 103= 27,000 W,with5% ToleranceCOLORVALUEB lack0 Brown1 Red2 Orange3 Yellow4 Green5 Blue6 Violet7 Gray8 White9 Table 2 Figure 8 RegularVariableResistor Symbols1/8 Watt1/4 Watt1/2 Watt-5-RESISTORSSELF TEST1. A flow of electrons through a material:a) Voltagec) Currentb) Resistanced) Conductance2. The pressure that pushes electrons through amaterial:a) Voltagec) Conductionb) Currentd) Resistance3. A material that has very high resistance to electronflow:a) Conductorc) Resistorb) Semiconductord) Insulator4.