DOCUMENT RESUME

ED 124 388 88 SE 019'611.

4 TITLE 4*. radio receivers Ninicourse Career 'Oriented. Pre- Technical Physics.. --t .

, TNSTITUTION Eallas Independent School District; Tex. arm AGENCY Bureau of Eiementary,and Secondary Education (DHEW/OE), Washington, D.C. PUB DATE 75 1PTE 44p0; Not available in hard copy due to Sarginal

0 legibility of original document;,Fok related . documents, see SE 018'322-333 and ,SE 019 609 -6'16 ... EDRS PRICB MF-$0.83 Plus Postage..HC NOt.lvailable from EDRS. DESCRIPTORS ,: tlectronics; Instructional Natekials; Physics;

11 *Program Guides; *Radio; * Science Activities; Science .Careers; Science Ecation; *Science materials; Secondarty Education; *Secondary School Science; Technical .Education w. 4 IDENTIFIERS 'Elteentary,Secondary Education Act Title III; ESEA* Ti le4111 ,.

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ABSTRACT ,,,

. This'instruct:Lonaa guide, intended, for student use, develops the subject of radio receiver* through a series of sequential activities. A technical development of the subject is pursued with examples stressing practical aspects, of theconcepts. Included in the minicourse are:(1) the rationale,.(2) terminal, behavioral objectives,(3) enabling-behavioralk o jectives., (4) . activities, (5) resource packages, and (6) evaltion materials. iv domponents of radio receivers are constructed b students. Thip unit is one of trey ve intended for use *in the second year of a two year vocationally o tented physics program (CP)

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************vp******************************************************* * ".66Cuments acquired by ERIC include many-informil,uilpublished * * materials noV available from, other-sources.ERIC makes every effort * * to. obtain the best copy available.Nevertheless, items of marginal * * reproducibility are oftenencountered and this affeCtsthe quality * * of the microfiche and hardcopy reproductions ERIC makesavailable * 4, viathe ERIC Document Reproduction Service (EDRS). EDRS is not * * responsible for the suality ofthe-original document. Reproductions * * supplied by EMS are the best thatcan be made from the original. * *********************************************************************** L U DEPARTME NT OF NEALTNNATIONALEDUCATiON INSTITUTE 'WELFARE OF EDUCATION svaorEeAO?NNEvv1,5 EMS"..:r:40 -2V CR vE:EV_A Cli--..4% :417 :MCA' 00,1,...APEverv 14S,f SEES ilif0. .SCFv.v A5 1Ef.1..E Eif .C C Z.PC) ;A:ow 'M- CAREER ORIENTED PRE-TTECHNICALPHYSIPS Radio IRceivers Minicourse .1gAr CNA. }IY C.*? :v EfvE IND 1974 -75 CAREER ORIENTED PRE.TTECILNICAL PHYSICS' RADIO RECEIVERS MINICOuRSE Marian High School Bellaire,By R. S. ConlyTexas V 1974 I' I r at. CAR)3ErbRIENTED tRE-TECHNICAL MYSICS RADIO RECEIVER4 MINICOUR4 ' andTheThis tothelp basic minicotirse principlesyou understand is designedof rdftio the to basicare test rather principles your simple.interest of radio in eleepronies receivers. by building a radio receiver _ . A radio transmitter emits energy in the:form posed4of an electromagnetic wave upon which sound Wave'frequencieq of voice or music haveThe beeninitial im- electromagnetic wave is galled the carrier wave. i Some of the:energy of the thetransmitted sound- frequency wave is inducedfrom the inthe carrier-and amplifiesot the radio this receiver.signal which is now a weak pulsating The radio circuit "separates" .:- Inelectric this coursecurrent. you will build a simple radiolreceivet u6ing vacuum tubes and make it work. The speaker transforms this weak electric current into a sound wave,again. -: [ In doing this, you will learn: (1) what eiectroMagnetic waves are. . .4, --.. ' -(2) how an antenna "picks-up" the electromagnetic (the si!Anal) how a radio receiver is:nadCr resonant with .; inclrming .,(6)(3).wat (5)(4)how howtransistors resonance thevacuum signal. tubes workis is work andi what'theyand. what arethey used all for'inused tor receivers. in receivers. t roduCedinto the receiver circuit. an' signal.-'. addition you Will build..a(9)(T)liolre6eivers holf-speakerssimple radiO work.separatereceiver usingthe information :101Ithe (sound) receiver frog pplifies the carrier the information. wave. r, 4TERMINAL BEHAVIORAL OBJECTIVE 4` Upon completion of this Ainicourse, you will demonstrate(a) building s simple radiotuning receiver in at andleast two radio stations. yourdemonstrating knowledge andthat skil: it works in radio by by; BEHAVIORAL OBJECTIVE No. 1 (b) correctly explaining how 'the radio throughoperates each component \o the speaker. ACTIVITY # starting with the antenna and working RESOURCE PACKAGE # Lets find outstarted. where youj are and get o withRead your Resource teacher. # 1-1"And dPscuss this -IgglieftW:-OBJECTIVEradioYoU wi.11 receiver. construct an antenna # Sor r antenna.Read'ReSourceACTIVITY # 2-i #k1 and erect4your RESOURCE PACKAGE#,2-1 YoucorrectlyBEHAVIORAL will, on dOBJET' IVE # 3' ine an electromagTicmpletion of this activity, ) activity 1-1, you may go onACTIVITY Ifto youActivity #and 3-1. your teacher agreed in fit. RESOURCE PACKAGE # 3-1.1 BEHAVIORALwave Ira. ation) OBJECTIVE . # 4 ACTIVITYandIf not,complete # read experimentsResource 3-1.1 1 & and2. 3-1.2 RESO*E PACKAGE # -1.1 relationshipactivity,You will, correctlyupbn between completion the4elCtricexp a n the and f this . ACTI=VITYRead Resource # 3-1:2 # 3-1.1 3 propagation.magneticthe magnetic wave components and the direction of an elec of ReiourceReii,!.d the Package selected # readings listed in RESOURCE PACKAGE I 3-1.2 .0 BEHAVIORALYou will, OBJEupon compl;tio7n-df-this-_____-____I-Hesource-Packagei. # 5-1.1 # 5 IVITY # 5-1 RESOURCE PACKAGE # 5-2.1 resonantlengthactivity, of at acorrectly adipole given antenna,to. frequency44calculate-the be 4. /ACTIVITY Read the selected readings # 5-1.2 listed in RESOURCE PACKAGE # 5-1.2 BEHAVIORAL OBJECTIVE 6, ResourceACTIVITY Package 4 6-1 # 5-1.2 RESOURCE PACKAGE # 6-1 You satisfactorily,circuitwill build of athe radio explainpower receiver supply how itfconvertsand Build the power supply circuit. .superhetrodyneceiver.I K-50 Kitradio* for re- 5 ube current.a.c.. line current into a d. partsavailable,1;cte:cription listlrf theisthe'sameand foundK-50 circuit Kit oncircuit, ispg.des- not 673 ACTIVITY # 6-2 RESOURCEManual,of the RCA 1973,PACKAGE Receiving RC R- 6-?29 Tube a. ResourceReadACTIVITY theResource ;#selectedPackage4 6-3 6-2 7/ readings6-3 listed in RESOURCE PACKAGE 1 6-3 4 *Kit K-50, 5 Tube'Superhetrodine d Radio'Receiver, CTA-KIT Co., 1407 Industrial Blvd. Elk Rifer, Minn. low YouBEHAVIORAL will assemble OBJECTIVE the # Pentagrid7 Circuit Assemble the canverter circuit.' # 7-1 RESOURCEK-50 Radio PACKAGE Receiver # 7-1 Kit andsatisfactorilyof thehow radio receiver what its:function and explain is t a omplishes-ihis, ACTIVITYRead Resource. 1# 7-1:2.7-2 # 7-1.1 RESOURCE PACKAGE ## 77-2 -1 : BEHAVIORAL OBJECTIVE fi 8' ACTIVITYResourceRead the # Package_7-2.selected8-1.1 readings listed in K-50 Radio Receiver Kit satiafactorilycircuitYou will of assemble the explainradio the receiver i.f.what amplifierits and ACTIVITYRead'ResourceAssemble # the8-1.2 i.f.8-1.2 circuit. RESOURCE PACKAGE F 8-1 this.function is and how it accomplisher ( ACTIVITYResourceRead the # selectedleakage8-2 8-2..readings listed in RESOURCE PACKAGE # 8-2 BEHAVIORAL OBJECTIVES # 9 /e-iCTIVITY #'9-1.1 K-50 Radio Receiver Kit IAr. lyaudioYou explain will amplifier assemble what its;f'unction the is and how ircuit and satisfactori- ACTIVITIES # 9-1.2 & 9-1.3dide detector - 1 Read-ResourceAssemble the detector # 9-1 circuit. RESOURCE PACKAGE # 9-1 it accomplishes this. .ResourceACTIVITYRead Package the selected# 9-2 readings listed'in 9-2 _ RESOURCE PACKAGE 9-2 -4- anSpeakerYouBEHAVIORAL will assemble circuitsOBJECTIVE the and #Power 10 will Amplifier sat- .AspembleACTIVITY thespeaker power, #circuits 10-1.1amplifier of ,theand radio. K-50 Radio Receiver kit df,eachtheirisfactorily function.is and expldin how they what accomplish the function ACTIVITYRead Resource.10-1.2 10-1.210-14 & 10-1.3 & 10-1.3 RESOURCE PACKAGE # 10 -1. YouBEHAVIORAL will make OBJECTIVE the measurements # 11 on ACTIVITYReadEnjoy Resourcethe '# radio.11-1 #- 11-1 and make the RESOURCE` ACKAGE A# 21-1 A__ yourBEHAVIORALexplain radio the circuit OBJECTIVEsignificance and #correctly 12 of each. o . ACTIVITYmeasurements # 12-1.1 indicated. . 1( rectifyYouamplify will an correctlysignals a.c.:current, and explain how howtransistors how transistors VisitACTIVITYRead activityan Electronics,12-1.2' # 12.1.1 Shop RESOURCE PACKAGEPACKAGE #f # 12.112.1 detect signals, ResourleReadACTIVITY the selected# 12-2 readings listed in . ' RESOURCE PACKAGE # 12-2 YouBEHAVIORAL OBJECTIVE # 13_ . build a transistorized super- BuildACTIVITY a transistorized # 131 radio receiver Heathkit*#Transistoiized GR-1008 RadiolRec. ofhetrOdynesatisfactorily this radio radio compare receiverexplain in howfunctionand thewill circuits to after discussion with your teacher. BentonThe Heath HarbOr$ Company Mich., 49022 those of the receiver yem 7 RESOURCE # 1-1 1 I ACTIVITY We will start building the radio receiver by constructing the antenna.1 Let!s build:4 radio receiver. ! You surely have some Idea., as to what an antenna-is-and how it finctions. From time to time during this mlnicourse, you will be asked to record Right! Let's .see what yoU knowor can figure Cgit your ideasi assumptions and s. serve.some measurementsas a reference in for your you notebook. later on. Fortha following questions, answer in your notebook, what Have a spiral bound notebook fbi. tiffs pu6ose and us? it. you already know and speculate freely, It(will Please write your` answers in your2.1. MakeRow notebook doa listyou for supposeof futurematerials the refetence_and sound you thinkof iroice-arAsic thhtdiscuss you themwil.1 is.transmitted'froi with need your to blild the antenna.on e lOcation to so many distant teacher.' 3. For the antenna you have planned,places as have radio you'given programs any-consideratiOn are? to the length? . 6.4.5. AHowlong Toradio what receivershould shOuld an themust antenna length be?of the antenna-be. related to?: ave some "signal" from which to_re:Produce sound. How in the world does An doIf notyou needknow tothe complete answers thisto each activity. of these questions and_antenna understand- wire strung the principles in-the air involved, get the radio signal? A , you probably presentIf not, knowledge, continue theerect activities your antenna in sequence. (see below) thenDiscuss go onthese to Activitywith your #5 teacherbefore proceedini. If you and.your teacher are satisfied with your Teacher Check,on page No. 17. ty ACTIVITY 2-1 Erect an Aitenna. RESO .CE "Ai 2-1 To erect 2 polesinsull&tors, or other strainmeans ofegg'insullators mounting the antear antenna you will need the followin f a outside. '2 to*3,inches* long, glass The Antenna may be 64 the-rbof,of a or porcelain. 4 - 21 buildingfeet-of BUTcopper tying antenna'wire, the antenna Solidlid.to tree,1' 12 Lcopperb1,14is wire NOT or advisablestranded copperwire,aresince thelimbesway both ih tine the wind. . Sufficient copper or galvanized wire to r ach rom, the ends ,IST the antenna wire to the ; - Sufficientsupport poles. insulated copper wire.to reach from one\end of the antenna wire Carter 'it:is; * 7 Tools required: mounted)Pliers, toknife, the'receiver-location. soldering iron', rosin core solder and thOse.necasaarYlo mount th s. up r Procedure The antenna should be reasonably high abo e the * . ft., aid 4 leer of. obSt6eles- such as other buildings,, trees, power lin s, etc. `Mounting the ancliiiiaz....41 15 '- rOof..kA of , a builAing- Mountis usually the antennagood. support poles 3 f apart" and mount the_antenna as shown.in the* t e li,eforesketch below. mounting the / antenna, Solder one e dpprox, d of the insulated lead-in hire to one. -e nd of.ttte - .0 O ,w3.11 enter the building.the, antenna wire. Support wire or This - 'should be the 'endcord.._#2° lasulator --Insulatornearest. he point where the diitenna 1 Spicier corinectioni -j Support If -polesrniix need a pulley wire., or cord ale 4alt, y,out Lead-into anfenna.wir.e wire=- ,and cordpull, here -t-o antenna lout. , 4 =EXPERIMENT il 3. Purpose:' TOt. determine:the - c ent in the,abtenna. Apparatus:CAUTION: I =0m4ltitaster with ver loNgtange a.c4,volts and a.c. amperes scales. improperly.Instruments,-' or measuring. electrical propert a are del. dii-tearid-Tria/-13o=Eamaged easily if Used c WHEN USING,AyOLTMETEROR AMMETER, WAYS TEST TO-BE SURE T-----. THE POLARITY OF THE METER IS RIGHT -. METERANDIt THATTHE IS CIRCUIT..TIPTHE'NETER IS NOT,THE NEEDLEOVERRAN 1:7ERRAGED, 4LECT A IGHER READINGdVES SCALE THE OR WRONGDIRECTION,REVERSEWANOTHER HIGHER-READINGI . I TESTrBY "TAPPING".tIGHTL D QUICKLY THE LAST._COtNEPTION Y CONNECTIGNSIF THE THOEDTT. Procedtre: antenna,lead-in wire (bare viva) to one instrumebt4ad, Set your matitestaf.'on the lOwest west a.c. volt t,,.,_, ... scale (l-,13:volis).. Connect theaiEili-g(the , a good ground cqnnedtion; water pipes ax:e-',a g6od ground. then tat, the other Beinstrument slare tbat lead thea to pipe is clean, at Observeampereis, with andscale. bright'record metal the metershowing readings wher in you tap'' it., your notebook: Repeat with the meter pia on the lo P t a.c. a Oi a ,f- 1-RESOURCE # 3-1.1 RADIO WAVES \.--- \ \ \ greatSoundACTIVITY wavesdistances. # 3-1lose so/Light waves once other hand do not lose much energy as they-traVel and ch energy as they- travelt4 hroukh any transmitting medium they cannot be heard .-- .; light.Cani be at areseen partat great of the distances. electrqmagnetic spectrum. Light waves are one of what we call eQ_ectromagnetic waves, they and radio woes, See Fig. 1. __. .. Electric. Rays Radio ',Infrared Visible UltIlaviolet - a s ; GAMMA Rays Cosmic Rays Produced by Radio 'Sun & Reat Su n-Lights ` . UVSurigc Lamps Machinesk-Rai SomeEmitted Radio-'` by From Space GeneratorsElectrIe- Transmitters' Nmces elk ActiveEleMents"&.` N. Wave 3 .1cx.104- 147 Amr 1 -m.-Decreasing Wave LP gth ( Reactions3Nuclear x 10 7 Length , ------__ Very Short Very Long ,, . = / . .-Inc-reasi -, ncy. Very High EnergyFrecriancy Very Low Y Low , -y*- IncreasingEnerl Very High. OT.sk:.....1 A 1 x 16-10.m. . * . radioT1 basic wave principle ,llpigg5i-hack" of radio the is soulidWave to impose to sound the radio waves on° aii4 electromagnetic (radio),wave and FIG. 1 reNiver where the sound wave component is "separated" let the and reproduced as a sound wave. tuafly the souiz wave, converted. into a, weak - electric , --' current which is imposed on the radio ire*. 4 I J. agrall o it is shav'in in rig. a2 momentA.- The how fr this .works. The radio ga're is ncy. 0/- sound waves (voicet and music} wave _of fixed single frequency and k o4 you. ',kno.When theMicrophone. sound signal i,s imposed, on the. radio wave,**4t isand done the$e inn suchsame frequencies appear ire the weak elvtric current generated by sPeakingThe amplitudeinttethp of such a current is- represented in the _wave diagram in F4 2 a. manner as} 5 have .the sound vary theSignal amplitude add to ofand the subtract radio' fro&wave, th'e this amplitilde process is of calle,ft the radio "amplltndevaoduiation". wave.. . . * Since the imposed sound' signal alters or AM: The wive diagram of .an AM wave 1..s .h..:lcimii,n Fig. 2 E.!. . c . f, !. r; :. 4 f,. j',. A Sound signals may also be apmbined 'with"radio waves In such II I" t 4 ' . ii !!. ?i 7.1.1 i.r7:7r4 !VIf, iik 1, li. :)!..-,,' ..i:!..: ,i0....., 0 resultinga.manner es.to Wave modulateis the Trequency of the =Ldid..wave. ailed "frequency modulation" or FM../A. The A. IinmOcivInt4d I 1 'i-i carrier 'signal a From't duency' modulated wave is shown in Fig: 2 D. above,you see, -Oat we should begin our study of ; I,radio by you' are going amining`the proPerties of electromdgnetic-Waves. ders tend radio operation; you shomild B. Audio signal, \." relationshipsTheunderstand -following involved. means whichhelp theyou signalto understand, reaches somethe radio.of the C.4 Modulated-D. Frequancy modulated signal carrier signal Y. NowCAUTION do these AGAIN two lab'expdriments, but before you do, a word of caution. WHEYimproperly.Instruients USING A-VOLTAETER for measuring OR electrical-propertiesAMMETER ALWAXS TEST I)are BE deliCatct SURETHAT'THE end-4,may FOLARMY be 6mF!.ged OF THE easilyMETER ISif RIGHT'used ANDMETERIN THATTHE IS CIRCUIT.THE OVERRANGED, METER IS NOT6PT.ECT OVERRANGED. A HIGHER READING SCALE OR ANOTHER HIGHER READING INSTR=NT. IF THE NEEDLE MOVES THE WRONG DIRECTION, REVERSE MIT TEST BYii!TAPPING".LIGHTLY AND QUICKLY THE BTIE RY CONNECTIONS. 'IF THE 445.T-CONNEOTT)N. Purpose:EXPERIMENTIf yOu have 1. not done these experiments Aeviously, do them now To demonstrate the relationships between electric currentCurrent (electric .Magnetic charge),Fields- ?.lotion.magnetic fields Write these up it your mptebook. A. Apparatus: and motion. Oneswitch galvanometer, and several 2 barlengthsof magnets, copper 1 6v battery,wire (bell 1 -wire). 20 * ohm , 1 compass, 1 . 6 ki'ife Intrbduction: In this experiment, you will observe and report on the relationship between electric . Procedure 1. currentv-_ (electric charge),Connect thea magnetic circuit fieldas\ shbwn and inmbtion. the following diagram. A c rm.-7'4 I' 6v DC if 2.0:A-4 le 0 * This resistance should be adjusted.to give a.very definite movement of the needle.Orieflt the setup Auch that the compass needle is pointing "to the north and so that the wire , ; Compass is directlylover the needle. ,*- Close the switch momentarily and observe. . Nowdirection. reverse.the wire leads to the battery. Close the switch momentarily ard 66-serve. This will cause the current to flow. in The opposite. . Assumptions: isOrient...the open. setup such 'Plat the wire is Writeat right the angles assumptions to the orcompass'needle conclusioyou when make the together switch with theClose evidence the switchto support, momentarily ttese and observe. and turn them in to your,teacher.- Teacher Checkf-----2.14g Procedure 2. procedure. Connect the divcuit as, shown in the following diagram. 7 You will need afhelper for this 0. CR ky rft---7-1\,Vi....--Galvanorneter' g t .fr Bar magnets supported . above table top by wooden blocks r- e r 1 ,i . 1 - 17 --40-- 45 cm.- s I --.-.I andseparated the magnets-should by a distance be of 1.5-2 CM, V. _ :'The Wire should a beGraspfast shaped nmtion,the aswires shownpass between the wire the downward magnets betweenand the .thegalvanometer two magnets. with that ie:111 pass between the ends Of the magnet... one hand on eacbLidre.Your helper should observe With .Itc Rleatthe galyanometer, as yOUpass the wire between the magnelp. except pass the wire'upward 'between the magnets again with .% 4 a fast motion. _Assumptions:- Write and turn them in td your teacher.. assumptions or bonclusilps you make together with the evidence , -Teacher Check to support these Proce fre 3 Connect the circuit as shown in the following diagram. 6v DC _25- 30 cm 1. 25-35 cm of wire, horizontal Switch OR Bur magnetsnearly supported_an so. 4Assumptions: ReversgClose the the switch leads momentarily on the battery and obser4e.and repeat.Write asSumptions or conelusione-yOum4e together with:th viderice to support these 1,14 and turn them in to your teacher. Teacher Chuck" . 1° / A little background information is neces8ary here so lets look into it. , --tiela is at rightYou angles will to recall the direction that a magneticof the current field isflOw:1 created by a current flog in a wire and that the magnetic In fact, any moving charge creates a 0 , a 'magnetic . ffelid and any challege,. moving or not, creates an electric field about-it. -7, t These two fields, 4the radio elecwi.o transmitter and the feeds magnetio a high fields, frequency are atIradio right frequency) angles to electriceach other and to -,represent current the antenna. stored eer.0 As this magneticTherf electriccurrent waves, flowsenergy called i radiated radio waves.by or..antenna (transmitter) exists in tree spice the antenna some of it is iadiatedsas energy into the atmosphere. These waves consist '2f a magnetic field and ameleclric (---'',sp-ere) as pagatedTheright energy, angles in a whichtodirection each is othersupplied at rightjust by asangles'to thethe transmitter,magnetic both. field is is equally a.'! right dided angles between the two fcields and is See Fig. 2 below.. F.Ping,an to the cirrIft flow in a wire. iectlagt.etoo 4 wave, it is pro:- propagated at'the-sDeed of light. componentElectric' lt'' A r- i'l 7-91-r-i- .." T#IF-01- * " #.: # # * #, a' '''', -, ii tti, ,7',...` / Direction'propagatio9, of componentMagnetic V 1 A7 In fact, any conduttor carryingen alteenatiug current radiates some energy as electromagnetic waves. However,.60frequency, cycles the/enerWrd perthe secondgreater (cps), the energy the energy of the ofrediationli. the electromagnetic waves is very low. e radiation7is directly proportional to its frequency ie, the greater the It turns out that the frequency of house At radio frequencies, current; /-7theradio750 higherto frequencies 29,000 'end kilocycles of arethe atsmectr theper lowsecond frequency (kc per end sec.), of the the electromagnetic energy is much spectrumgreater. arid that the waves at (X -ray,. gamma & cosmic rays) have much higher frequencies andenergies. No4ice however, that TheourselvesIn fact, followinech whilefrom thewe dohi nothing t Ihdicatesthe.approximate frequency ranges for radioer.'frequencY tran=issions. radiations. o protect ourselves from radio-waves, ye take elaborate =eats to protect The values are expressed locycles per second Nc). 88,000 1 216,000 r qti en cy, kc 400 535 750 Marine oroadcasiStandard 170,0 ,,Marine 5509 ,Amateur radio 29,000. 54,000 T V i74,090 T V As we have/seen, when an antenna is,energized ad, when connected, to an operating tran FIG7_2 ter, the antenna t radiatestransmitter, energy is as exposed electromagnetic to radio waves.-waves, someConversely: of the mfwhen (radio an antenna frequency) note energyconnected is inducedto an oper in the wavewillantenna be asvery the much Waves weaker move thanpast inthe the antenna. transmitting-form antenna. as it had in the transmitting antenna.; In the receiving' antenna:, it will have the tame frequencyHowever, and the induced current ih, the receiving antenna Because the-induced current-is_weak, antenna a critical.notlength critical. is often mprtant However, as the frequenb' increases, the relative length of the wave and the_antenna becomes In the iandrd'brciadcast. rangeiof frequencies, the length of the antenna is or enrichment, look up Plank's Constant and Plank's Quantum Hypothesis. / Modern Physics: jun,I Metcalf, Williams '.,,RESOURCEr.1;,' PACKAGE #3 -1.2 Holt, Rinehart & Winston 1.964 Superposition Selected Readings .. , Pages 289 The Electromagnetic SpectrumTheory -. - . 33333172. TheGroundElectromagnetic Quantum & Sky Theory `Wave Radi;tion -, 655-6338-9 --'--"N These topicA may be found in other Physics texts as well P 657

-16- 1 .Z In the last activity y6.1 found that the radio wave TheRESOURCE Antenna 5-1 induceq in the antenna is of the same freqdency, / waveislow; accomplishedlength it is anda weak form by signal. adjustingas the transmitted the length wave of theand antennathat the to energy correspond of the to wave the (thewave signal)length ofis thevery Since the signal is so weak, we must do what we can to enhance it This ropeFirstdesired or obtain signal.a heavy a standingfishing cord,wave generator8 to 10 ft. and long. generate a standing wave.- Or obtain a piece o The lowing discussion will help you to understand, the reason for t Tie one end to a fixed object and generate a standing light weight waveLetYou inusmay theassume want ropejby toa wirelook vibrating oneup.standing half the as otherlongwaves as endin an aup rfPhysics and wave. down book. while adjusting the tension on the,roPe by pulling. The electromagnetic radio frequency wave (rf) - antennainduces areah rfthe voltage same., anda' standingcurrent in'thewave results antenna. in the antenna and restnance is established. If the wave length'and the "electrical" length of the Look at it this way. + Refer to FIG.2-1 below. - --- Current For thisdiscussion, you must set aside the idea Voltage- thatcurrent one musttoimpulse flow. have will a closed be reflected circuit atin order for a With radio frequency,'a ?foliage or Yee end of the A closedSystem assuch a lightingas a standing circuit. rf waveYou shotin'aiWired.s,known d recall that theas ainduced resonant rf circuitis composed although of.e. the voltage circuit and-1/2 may a Wavenot be --91 wire much as light is reflected bY-s. mirror. 'be atthecurrent a maximum.voltage cotpenent. is'applied, it is at the positive peak of its cycle, the voltage at the end of the wire will A voltage itrpulseowillNow travelsuppose along that thewe imposewir ilnd an uponrf voltage reaching.the at one endend ofof thethe'wire. mire one If at the instant half cycle later, two things happen: a) the voltage impulseis reflected back along the wire, and standingThe result wave Of addingofvoltage, the voltage impulses, those-travellingb) the vatage out-and of,the those ap pliedreflected rf will b ack,be at will its.negative be a peak, since the wire is.1/2 wave length long. It is not a static Wave 'per se', but will.appear to be static or standing voltagesince it alongis thl! the result wire with an rf meter, yt of the outgoing and reflected veitage components. .4!'r would find the voltag5 to_be high.at the ends and. practically If,you cou.ld.measure the practicallyzero at the zero center. at the ends and.at &maxijeum near.S the center of the wire. Likewise, if you could measure the current" along the wire, you would find it The current component is also Uptransmitter..reflected to now, youhence haveActually, it Pr.Obahlytoo changeithe samethought direction kind ofof the'applied aonce standing each wavecycle.voltage results as coming from inducedfrom an energyrf generator that results such asf'.'rom a Theelectromagnetic standing wave wavesresults passing because an the antenna. antenna wire .is one half wave length long electrically,. hence . . Nowandresonance we the come signal results.to calculating,the transmitted or 1.elagthofreceived would wire notthat be will-be as strong. one half wave length electrically., First If the wire were significantly longer or shorter, this resonance would not result. Thelet's relationship *exa mine theis: relationshipbetween-frequency, velocity and wave length of transverse waves. velocity = wave length x frequency and 1.`.a true for transverse-waves, the consistant units for these variables are velocity v = fA in or X = Imeters/sec f or fdbt/sec- r wavefrequency length in meterscycles/sec-18- or -feet cycles/sec t The speed of light& radio waves iSapprOx. 300,00iim mefrsfset. ° Calculate the wave length in meters of,radip-wavesaving'tlie following 9 Okt/sec cle (kc) = 1000 cycles. 3,8,00 kg/iec 14,2504Nc7 tec frequencies:, WeNOTE:can make calculateOne most kilo of theour wavemeasurements length in in feet. feet so it would be convenient to Recalling that a meter is 39.37 inches, have formula by which weTeacher Check 0 calculate )the calculate speed of -4he light wave in length feet per,second.of the three frequencies above in feet. Teacher Check'( 1 Thean-rf calcillations,'we wave in a wire have is amade little are lessvalid than,in for the freerf wave space'and travelling due to in'fr6e space.other factors,_Since the an speedadjustment of must Teacher Check 'be made'to calculate the resonant length of-a,dipole anten -length of half wave anteriO-a-Afeeil:-- The formula used is:-frequency in468,000 kc which is thesaille as 1 kc = 1000cycles;. length of half'1 Mcwave = 1,000,000 cycles; ntenna tft) 1 le =-71000 kc. freq... Mc 468 * the length of the antenna Notewire: that in calculating the length of the antenna, we haire equated the wave length of the erf with 4a. °:,. YouCalculate can now the caitUlate length ofthe a lengthdipole ofantenna a halfwave, for the dipole thr e antennafrequencies for amentioned radio 19 receiver or transmitter.abOvt-, .Teacher CheckLi ndarstanding Radio American Radio League : RESOURCE PACKAGE # 1963 Antennas & 'Feeders. ,Selected Reading 4' Pages 95-96 A Modern Physics Dull, Metcalf & Williams' tzp, Selected Reading Holt, Rinehart t Winston I AntennasDipole Antennas .Pages_ 652.. '653/ O

-20- . post, ASSESSMENT A" 2.3 Write WhichSpacialy, compon nts/properties are thought of as, being on these aplanes? definition of el lectromagnetic radiation can be described using 3 mutually radiation. perpendicular planes. 3. ArrangeCalculate the thefollowing le;lkikof electromagnetic the wire necessary waves in.iorderto-form a resonant dip -lee a)antenna 14,250 kc. b) 1500 c) -750 kc. of,.b.escending energy. d) 28,650.kc. for.radio waves of e) light. 5. 'Whe'reHow isis itthe divided? energy thought of as being stored in an electromagneticave?-a) 14,300kc: . b) 920, kc 1 RESOWTWE # 6-1 - - ACTIVITY-4i Now you. are ready, -to startbaildingthe radio itself. ., -..1 , ) All radios that operate on houge current and(115 tOlienge v, 6 dycle) thd`voltage must have to a thepower desireVevels. supply to.change-the 115 v-g.c. curren:t.to -,.:44, , \ This is accomplished in what we call the ffDOwer supply".4 a direct current (d.c.).J/, 9 I..i your radlo,4ne'pOwer.supply is the circuit\' involving fhe tube,,. type 35W4'; on the circuit Doverdiagram, ampliifier it tube type 5005. cpote that the filamentg(pins 3& 4) of the otherlour tubes are connected xtends from the 115 v a.c. line plug to the connections to the speaker cii="cuip...and to the . in this ' dircuit. 41. e othe familiar witha Aumber of,the0 synil;asFrom here on you will be. reading the circuit diagrams of the fadio.and in the references. , used in radio wqtk, but untif,JOU:do, Use:the chart of You' will symbols on page 140..of this ianicourse, Assemble'this power supply now. 1r A In operation; the power supply must tave a. ioa4 in order to function. t 44 ofWe willwork substitut4before, you a should2000 ,ohm read resister pages 119 as thru_131the load forof Chaptertesting 7,purposes. Understanding Radio, 1963, published by o Ifyou,have not done this kind howthe to;:pr_e_venf_damageteAmerican Rgdio Relay League.comp rents Be sure that the leads, to the 5005 and the .speaker are connected to a 2000 ohm resistor using alligator In this reference you will.beg4ired'helpful hints on.how-to solder, solering,,how to prevent-t!hum" in yoUr radio; etc. immediately.indicatedclips; not onsoldered the diagram. connections,:-since this is temporary. (Try to make this opening and closing Plug the circilit in to a 115.v a.c. Outlet. one otion.) Double cheer t the Wiring to be dare it is as ndt Now c ose the switch and open it happens, nothpig "blows," or . .\' starts .smoking,\Close the switch 1.-Obtain-Observe a multi th' filam Tits of each o dter end test the Following ad indicated, d oyergthe power supply. e tubes. -22- "4. + Set the meter on an a.c. volt scale that includes 120 a.:good scale for this.) b' - - lead topin'No. 6 of the 37,44_and the other one to one of the . _..9 .switch.. Touch one m4te ' . - r. / Read and record the / '1.- S /1-Setthemeteronad.c. to the end of the lead to tUbe.250054and thq, .1 volt scale that inciuderi// 150v. positive lead to the leadsto the speaker circuit Touch the negative lead of the met , neck that When you first make thiiconnection, just tap the last connection momentarily to . . JD the polarity of the meter is right. If the Teter needle m9ves the wrong direction, reverse, ' . .- R4adthe leads of the meter. <" the voltage, record it and note that is now a direct curlent (read witlia,d.p, , 4 meter), + If you pave ran oscilloscope, connect it,to t .0, Output of the 3514 and otserve 'the wave fo'em. k_. ACTVITY # 6-1.2 ) 1 / 4' Assumption(s): Based on your obeiAtions and recalling that,an electric current is 4 floW- of electrons, ' . il!N . ,,,, ) ,make'an assumptionts)ou may about use bowthe the'a.c.simplified current diagram wa-changed of the circuit into a belOw. d.e, current by the tube. 1.1.7ii:oa aloe 2000 ohm resister -.-:-It - __.: .7.4: 1L. A. . . Afteryiiu have madeand:i.eCor4p4 yO4r assumptions'', discuss. hse wifil?yonr :teichai'. ell;aCiaerT4eCkli IS .."N ,. .. -0, s -----> RESOUR0fr# 6-2' ,- ACTIVITY # 6 -. 2-- ,..?, ...--- ,.., Now'let.'s. check your assumpton(sli - ---, , . You pIlepably noticed that when you-co. neCtethe tubeThe tubeto the a.c. current, o3e 'element yecome quite used (type 50W4) is khOwn as a-Tiod9, which means that is a two (di) v . element tube.. hot.' This is. the heater; it meats- .e filamW (called the cathode): adjacent -th-----.-- . ._- to it... , To, her these two con- . Stitu-ke one elment; in some tubes the heater itself is the cathOde. itself r . When the-cathode4 is ated, it' gives , . off electrons, creating A cloud of electrons, calledphenortonam the is Xur..: as the Thermionic FmiSsionWthe . ace charge, in the glass envelop of the ... ,.....-__= _ S'ecoed eaemest in your ".,ube is the plate, usually in .1 a metal-plate or cylinder pled near the oathode. -If the plate-is made more positive k t (not necessarily 4,0itiven electric but current less negative) will 'f'.i_OW than in the caiho 1 e plate circuit. , some of the will be ettraLlted to the plate and See Fig.'6-2 below. . CJ 0 ?c Plate ThefrcmIn plate thisthe "A"figure,ithecircuit battery, consists cathodethrough Of isthe heated cathode by andan elerxrcisback to the current "A"battery: flowItg he c9nnection to' the, positive .- .with.negative respect( +) side to(-) oft sidethe "Ie.battery,of the tho--"B cathode Since the ivgative'side of the "B" battery thode. Note that tile plate is more positive--at tery and the wire lead to the . . Theis hotconnect cethode create to the cathode. Now'suppost that the Circbit'is in operation. Thes-r HI BfrIft. 111111. I. are more stro4ly attract a space crargedf,(negative) electrons.to the plate,..(the;plate being more pogitive) - "A" 6-,2 84M wherethanflow they-replaceto as the an cathode.electric thoSethat current have to As the electrenCare.eaptured by the plateAiattery they and back to the. cathodeen emitted., -- Now suppose That we rever e the leads on the .'=B" battery as shown on Fig.e1eIn this6-3.atrons case of thethe plateisspa ;e ChargeMore n willgative ot thanbe attracted -the cathode.hence to`theplate the Thus,and therea currentwill w-: l.be noflowin current the in plate the.pl cir it Of a only when # -:nnating theyour plate currentpower is supply, mare(a.e.) positive you and aid did than find the a d.cathode. Itetteries, you rent in the ou sed an alter- t of 11A111 the tube. The diode tube works in the same ner as described for COt\D heater to heat. Fig. 6-3 Hence the tube fl B" aocuMulates4 theaMent- direct a current from the battery.. The a.c. current acathode space/charge: just as an a.c. current causes an electric space . You will recall?tpat the voltage of an ac heats the fil- nectedcuirent to changesone side. polarity of the acfrom line, posizive to negative tie polarity of- the pl each cyCle. e will' swing from very positive to very neg- Since the plate of the tube is con- . atiVe as the ac voltage does. While hone ApOled voltage (ac line) /7 electronsit4Pis positive, fromLthe the cathode tube will to thepass Plate tanca . sx plate circuit. plate,ative, but no whencurrent the plate1.dll isflow,in .p.eg- the The result is a ac line Fig.6-4 pulsatinggrams :in directFifi. current . . may help you to The. dia- tifier.Simplified diagram of a diode rec-. The heater circuit has been., understand this. 64, Moteoftheomitted. current plate cathode;that isthe (dc) positift so,thatdc flowcurrent with!.respectthroggh Is pulsating... the load.to'\. The current ,flaws only when only half cycles Current output.oCtube 7 In your ptiwer supply circuit, note t t the plate (pin No.5) is connected to the ac line lienCe it swirrgs platethrough.the'spacefro'm (pin,No.T) positive toof negatiiechargethe power and as'the amplifierback acto voltagethe tube, ac line.does.50C, through the speaker coil to the catkode'of the 35W4, When the 1'youplate areis p6Sitive,wondering awhere current all flowsof these from electrons the thecome-from, electrons notethat that flow the incatho4 the plateof ttie - circuits5005 is connerNtedof the%5005 toand the th other'fside of the ac line and supplies 3511 0

*In

-26- , RESOURCE PACKAGE # -8 Modern Physics rurt ; Metcalf f 'Williams Selected Readings. Holt, Rimhart Pt 607 Winston 064 4 PowerDiodeTypes ofSuppliesCharacteris Er ii ics s 7 '445-6481608-609607-608 . The Radio Amateurti Handb.:-ok. TheVacuuM American Tube RadioPrinciples. Relay Selected Readings 14eag4 Ppgfs 61-03 w. 1974 Power Supplies: RectifierIntroducticin Circuits ;." 1 05 4 'ACTIVITY4 7-i.1, RESOURCE H 1-1 amplifierthe Ferrite circuits. antenna, the oscillator circuit and .Assemblethe coupling ,*?:`t trigpsformer Pentagrid Converter between thecircuit converter of the-radio and the receiver, kit circuit will include ACTIVITY # 7-1.2 \ . condensers C5 Look at the circuit diagram. of the converter, the 12BE6 tine. & C6 form an oscillator, the frequency of which can be controlled. . . . The t. The voltage (rf) outputl' and variable , to-anotherof1 this oscilletor grid (pin is 7) fed of tothe the same rid tube. (.in 1) of the 12BE6 while the rf-Voltage Thus two (2)- frequencies are fed to' the tube;,a fixed frequency, . from the antenna, i.....s fed frequencies.from the oscillator and the rf frequency from the antenn *1 1 which' may contain oa number of modulated a. 4 . . please do iwo things. What do You suppose the purpose of this tube and converter circuit is'? . f r . n answering this question, \ . . a) Study the circuit and think recordnowabout know. it your in termsassumption. 'of Then make an a sumption.as to what the circuit does (what its function is) and Notei/t-is not so important at this point that-You:make the "right" the brief description abov.e,and what you b) After-you have made your assumptions,anassumption assumption look but or up,' itmodel-f5P-the is important phenotonum that you develoyou $ udy. the facilityequency.Conversion" to analyze information or "Intermediate and make Complete a) and b) above and discussofFrequencies" the theseconverter within the circuit.. references .given on page,lio. 3Q and write a brief, summary of the fudction your -28- eacher-before you go on. Teacher Check Your summary of the function Of the converter circuitTwofrom should (2) the rf expresithe oscillatorsignals are fo..ilOwingand fed the to otherthe ideas: converter an rf signal'from,the'antenna. tube (12BE6)ti ofte isa.single fixdd frequency The tubd "mixes'_theSe frequencies and theoutput+ a frequep4 of the which tube; is the thethe plate Frequenciesdifference current, of isthe a twocomplex input mixture frequencies. which inclu es: of both input signals. IL go; - The tuned circuit in.is thethe differenceoutput of betweenthe+ plateaifrequency 'fie is twotuned inputwhich to selectfrequencies.is the onlysum ofthe the7two,inputfrequencies. beat frequencythat This beat frequency still carries the oforsound transferredthe modulation proper frequencyto ofthe its:amplitude. amplifier to cause tube. resonance_in the Tuned circuit. This selected frequency is the Theon. other frequencies are rejected because they are not one that will.be coupled I4 f r .odern Physics Metcalf & Williams RESOURCE PACKAGE # 7-2 Selected Readings' * Holes Rinehart & WinstoA 1964 PentodeFrequencyTriodes Can Conversion Amplify Pages 642764349-611 0 ROARIK:eiving Tube Manual ° RCA RC 29 d Readings. , di 1973 , , Cdniersion , Pgs, 7 77 - 789 Radio Amateur'S Handb k Tile AmericanFrequTy RadioRelay League . - 1 1974 \ ScreenTriode,/, Grid Tubes \(To Power Amplifiets)Selected Reading Pages 6i_ -67 , ACTIVITY # 8-1.1 RESOURCE # 8-1 theACTIVITY coupling #18-1.2 transformer between Assemble the'intermediate fro 4ency if) amplifier circuit of the radio receiver.' This wit he i.f. the diode detector. / include 4 circuit. --irOm/what you have done and read Let's see. Stu the circuit and-the tube and speculate as to what its function is. so far, you may have a gdod idea as to.:cae function,of this , Record your assumption(s). and disc Now that YO have recorded your assumption, let's examine it. s these with your teacher- ,We have a vacuum tubith a cathode, Teacher Check r --I p stitutaate.and f.1ate and t a triaile!hich will amplify..e No. 1 -grid, the one connected to theee grids.output of the converter. This makes it a , five-elements. Recalling that the converter output consists of an ac signal (con- Let's consider first the cathode, the This much of the tube con- thetain signal ng an whichac voltage contains component), the informationlified and acthat signal (that an ac ofis signal thethe samesound applied wave or audiotoform the infrequency). grid the ofplate a Circuit, produces we see an. that the circuit merely amplifieS The other two-grids ACTIVITYmerely improve #: the Read\the selected readings ligted.in Resource Pack4ge # 8-2.per'ormance of the tube but do not alter its. function as an amplifier. \ Aj / _, Modern PhySics Dull, Metcalf & Williams . RESOUKE PACKAGE # 8-2 - ' .1964. % Selected Readings. Holt, Rinehart & Wingtte. %. RCA Receiving Amplifier Circuits, RCA Selected Readin' RC-29 Pages 830-634 1).73 The Radlo Amateur The American Radio -Relay League Amplifnaition (To Class Power Ampli:fiers) Fages 24-28 19'4 plification(through Casc Selected Reading e ) ' Pages 64-tc ACTIVITY Assemble the diode 9-1.1 detector- audio emplifi RESOURCE # r9-1 circuit up to the connections to the power amplifier ACTIVITYtube 5005. # 9-1.2 The circuit you have just completed is a-combination of two functions; detection by a diode and amplification of the audio signal by a *lode. From what you know about ra o circuits and what ever help or references you want to 1po i . . 4F. up, Make ACTIVITY1discussan assumption these 9-1.3 withas to yolir now teacthese er. o functl-ons are ccompiished in one tube. Record yotr assumptionsTeacher and Check / -7- ofthe asame. 60 cycle ac line current. When you were bui/ ing the ppwer s pply, you found out how diode8The difference.teingwork. ,The principle that, here i, thipis-Nzxactly circuit, we. have an i.f. ac current on the plate instead in the 120.6 tube, there are 3 plates. The plates for the diode section = Theare third/on pins plate 5 and (pin 6. 7) is the plate for the-.t.rjoae:sectilon of the tube. One of these 'is connected'to the cathode and does not function in this circuit. As the i.f. output voltage from ,/ morethe preo eding tuned coupling'Circuitoscillates from more t less following the i.f. voltage. 0 .--7 Since the i.f. voltage v less positive and back, the/tube conducts iations.were caused by the audio ophefre, endyOriginal (a. P,} a.f, current. . curn ',KgayTused to more t iall All weneed to o now is to amp ify\it and- chang,itto the rf from curr an nt, af theaignal diode into plate voltage is now a replica \ /a sound:wave again. You foundX out earlier that triode tubes woo3&applify -c / The ac signal is the plate current .-: ,,- from the'diode platetakes viaplace the just couplei as it did in the anecondenser 1.4: amplifier. to tpegrid (12BE6) of tibethe tube.andthe.amplified af signais'fed tiarOgia _. 2 a/signa. The amplification a *condenser to "the grid of the power amplified tube. , r -33- e ' RESOURCE PACKAGE # 9-2 , Mgdern Physics,, BIlil 1 ' et calf & Williams Holt, ,,Rinehart & - ` inston ,f . , )/ . , / Seleo4ed Reading - . . / , , Detection . . 'Pages - 643-644 RCA Receiving Tube Manua/ -----S'ele(cteli-Reading it RCA RC-29 - 1973 Detectioq . . Pages 19-20 . . The. Radio:Aihteur'S Hal1dbook The Amepi,can ,Ra.dio Relay League 1974 . / Detection and Detectors Selected Reading .- 4 Pages 237L242 ; RESOURCE # ACTIVITY if 10-1.1 . . r `We will do some testing first. 'Assemble the power amplifier and speaker circuits' but Accnot place the chassi DO NOT CONNECT THE IO T.0-1SOURCE OF POWER YET. -. in the cabinet ...../yet:. \ .r, C to be sure that you have the. 'Take the assembly instructio tire circuit corr connected. ufacturer and check eac a step of the inatruetions '.an assumption ACTIVITYas:to what #'10 the -1.2 function of this Circuit is. \Also -"Examinethe find out what power you can about plifier circuit and, based on what you new know about rad and t bes,\make r iffier ,differs from theDiscuss previous your amplifier assumption(s) stage. and finding with yclut tJeache . O -CO ACTIVI # ,10 -1.3 Teaphe Checki . 7-7-, .., , . ro .u. go on. , 0 Pleasespeaker. - corn.1et Activity 10-1.2 before The purpose of thp power amplifier In the previous amplifier e12AV6), the tube,was designed to maximize voltage amplification,-not \ %be is to deliver a relatively large amount of power $ to the power output. In thid amplifier, the des'gn-of the tube sacrifiees voltage 2n to incre se power / . tput. toIf the speaker.speaker is to produce sound,-ene gy (power) is required and this must come from the. It),t-s true that the power amplifier-tubedoes amplify -the Voltage to / \ , degiee,,but t ut signal -, is incidental to, the er ampilfication function:\ ,.' ACTIVITY # 101:11- , a \ . \ / After you ,have completed the circuit check using the anufacturers instructiond / lug VaP PcAfe .cord. \ . lir.et-though;into a 115 v ac 'outlet andoSave some fun with...yglik>radi CAUTIOI4 AlhoUgh most-of tht cirp#4s the for:a while. -Don't putrtdiO the 'ere chaqsiS low vOltgF, ere--are some )' the cabinet ircatageS , a in excess of 200v. .1Do not toucE bare wire or conne -35- ions in hdndling the set.whi it is plugged in".., 0

, RESOURCE # theA6T 011owl Y.# it -a.a the',Jhassis measurements using a multitester. on its aide,. plug in the radio and let,- it warn _ , p. Tune'in 'sitro is not-desigried for The measu . nents you masse on the radio, with/ theimuItitewter . but they will be relative .. -----..e._ _. will not be accurate sincethe meter \ - A. , ;b: each tube Set(except the multieSterthe 35 W , on an ac vol and the chassis. scale including 150 v and test the voltage betwe Record the volt and explain the rsults the piaTie yo / . i B. If ou have notebook,q an osci'lloscop4apAnct41 W - 41 f I. * the ) plate of each tube Soe at a time) and a erve tone i Sketch tie newave wave 'forms form.for in your ()tech notebook, paying--particular attention to the ,:''' amplitude of each -wave form. \\ % and 'explain t14 differences in termS,ofiefUnctionaf\ . ,,i, tA'''s N /T e radio y U: have .uilt / has a' bui14-4n fer,ite antenna. / - In, this experimenf:. we will 4 / the externale. antenna that you built in addition . . , Place the completed chassis in the, cabinet, , e to thebuiit-inq,a1.6Plug=in thy' radio ne /,s- .--. .., titenn , 1)tune Now in withouta station.'' changing-the Adjust theOrientation'of-the molumeto a' low radbut caMfOrtable le, el4 anddwith/.,, it filaying, wrapvseveral turns 4-,-. "v'the ead-in and 2) XoU,have noticed how theNoteof thethe endeffect of theof addingleadin e3wire'arouna additiOnal,tUrn. the / . yo ime of portable radios v radio case in the vacinity of tht ferrite,ana. - . thenis changed.rotate it4')zi the horizo Remove :the external antenna pland'until--/ the and adjust alum% diminishes to itsthqY.4.1142Of lowest yoll4 radii; to a lowlevel as the orie ntation of thekradio 3) During these.. experimentsthe eXternal,afitethen1.., rewrap'the external antenna jead-in. , Not the difference. but:merelywrapped fraund the, rOiO:catioet. V 6- a has not be connected directly to the rad4o411,:\.,,,..4 3 locikaroundYour problem4nowup the referen'ee:s, radio is.to thetb ask figure,radio's: people you...knowantenna Aystem. and. fknally discuss it with your teacher. _out. tthr or why- rf energy is transferred from the wire, wrapped Mink &about it using 'what you rfow know, What,,, electricallyC speaking,4 dots the :wire wrapped around the cabinet -co stitutel o A Solid State Devices Diodes & Trantistors RESOURCE # 127.1 * or ACTIVITY # 12-14 ,, In/ the radio receivez you have made, vacuum tubes were used-for the following functiOn:,1)to rectify . tan ac c information from the,darrier signal and-,5) to supplyrent, the 2)a.f. to signalproduce with an intermediateenough power frequency,to operate 3)the to ampl ify the signal, 4) to detect (separate) N . transistors.Inspeaker. a subsequent activity, you will build a transistorized radioo" In transistorized' radios, diodes (solid state diodes) and transistors perform all of these functions. receiver so-we need to 'bone-up' a bit "Before you go_ any farther,-.What- Whatwrite, they a are:brief made. summery of. they are used for. all you know-Abgnt transistors. 'a 7 Answer such as: HowRelative tranhistors size -of work. transistors and vacuum tubes. the advantages .of transistors vs va ubes are: Go' ahead and specula6 freely uhing',A1A/that you have learned. , ACTIVITY # 12-1.2 . . // . F transistors. Having prepared your summary, you are now prepared to ask some questions and to f ind,out more,aboutGo to an, r eActronics store or an electrOnibs repairkshcip (or to some one you know who is = . youskilled find outin electronicsthen discuss especially with your 'radio)teacher. and find out all you can about transistors. hhke notes of what*. erencesACTIVITY and # 12-2do theSelected readings listed in ResourceAfter 12-2.you have / discusse/ d your knowledge of dioAes and traniibtors with; your teach These.,are arranged in Teacher .Cheek rder`of increasing Obtain the ref-, twowithdifficulty are-recommendedthe first and one detail. and as continuea minimum. on until you achieve theilevel of understanding,that suits Sion. If this is your first 'brush' with transistors, you probably will want to start 0 The fir,st Modern Physics Dull, Metcalf & Williams . - 'RESOURCE PACKAGE # 12.-2 Selected Readings. olt,vRinehart & Winston 1564 . Crystals Are Used as Diodes :.9 Pages 620 . t ..The P.41-JunctiOnP-:and-NTransistors Semicounductors I 622621-622620-621 -623 . TransistorTwo Types ofAmplification Junction Transistors . 623-.6N624 RCA Transistor, Tbyristor &'Diode Manual ' Selected'Readin--RCA SC-15 1971 DetectorsBipolar-Materials, Transistors' Junctions Devices ' Pages 89-9012-20 (to Biasing)3_11 The Radio Amateur's. Handbook The American-Radid Relay League Selected R adings a J974 SemiconductorDetectionTransistqrs & DetectorsDevices Pages 8.3-91797§3 Filmstrip: How Transistors.Work4 . -237-238 . N.- ACTIVITX RES9I3Ra 1113-1 built.Heathkit Build a #GR--lopq 'tre.nsistriltd 'is suggested as a godd one and one that is, comparable to the vacuum .t radio.. 0 ube set you have a k o

0 OLS USED IN RADIO T.--*Incert)* rnA-milliammeterA-V- ammeter voltmeter propriate word - . or ,M SingleMulticell cell ' 'Chassis Eafth nna Meadset__. crystal METERS MOTORS BATTERIES ; GROUNDS - Microphone r Speakerf I Pilot lamp of Bipolar Transistors NPN G PNP 04\C Semiconductor Diode -Of-- GridlieaferELECTRON'Filament TUBE. ELEMENTS 1 -tompL or Plate Deflection plates Indirectly' heatedcathode >-- Triode.' Pentode TUBES Air corein= rTYY-N rf choke- Air core ._)..J Yst - Adjustable1NDUC'TOR iron core S trYTIM Electrolytic ° Fixed Variable TRAN -S FORMERS Iron core Adjustable/ a . 1. °