radio sangraahi

radio sangraahi

radio sangraahi (radio receiver) ek vidyut paripth hai jo vidyutachumbakeeya tarangon ke roop mein upalabdh sanketon ko entena ke dvaara grahan karne ke baad iska samyak prasanskaran karte hue ant mein dhvani ya kisi anya upayogi roop mein prastut karta hai.

anukram

parichay evam itihaas

radio tarangon ke utpaadan evam unke gunon ke adhyayan ka prayaas sarvapratham haainarikh hertj ne san‌ 1887 mein kiya tha. apne itihaas prasiddh prayog mein radio tarangon ke utpaadan ki vyavastha dvaara utpann tarangon ko unhonne swayam hi sfulingon ke roop mein do ghundiyon (knobs) ke beech praapt kiya tha jo taar ke ek fande ke donon siron par sthit theen. hart‌aas ke is praarambhik prayog ne radio tarangon ki grahan vidhaaon ki sambhaavana ke sanket diye the, jinke aadhaar par kaarya karte hue olivr lodge ne san‌ 1894 mein England mein ek vishesh prakaar ke sansoochak (detector) ka nirmaan kiya, jo radio tarangon ko shravya aavrutti ki tarangon mein parivrtit kar sakta tha. yeh sansoochak vastut: kaaainch ki ek nalika thi, jismein dhaatu-retan bhara hua tha. is sansoochak ko ek entena tatha ek samasvarit paripth (tuned circuit) se sanyut kar pratham radio sangraahi ka nirmaan kiya gaya tha. is prakaar betaar sanchaar pranaali ke sangraahi ghatak ki parikalpana karne aur usaka pratham upayogi roop prastut karne ka shreya olivr lodge ko hi hai. lodge ne apni is vishesh vyavastha dvaara pratham radio sangraahi ka nirmaan safalataapoorvak kar use peteint karaaya. lodge ki safalta se protsaahit hokar anek vaigyaaniko ne nae nae sansoochakon ka nirmaan kiya. inmein goolyelmo maarkoni ne chunbakeeya prakaar ke sansoochakon ki, vreelaind tatha fesnaden ne vidyut‌ vishleshya prakaar ke tatha li di faarest (Lee De Forest) ne sakriya vidyudvishleshya prakaar ke sansoochakon ki rachana ki. isi cheshtaakram mein anek kristal sansoochak (crystal detectors) bhi bane, jinmein kaarborandam, gailena, lauh paairaaiton (iron pyrites) ityaadi ke kristal prayukt hue.

san‌ 1904 mein J. A. fleming ne dvidhruvi vaalbon ka nirmaan kar, radio sanchaar pranaali ke vikaas ke itihaas mein nae adhyaaya ka sootrapaat kiya. sansoochak ke roop mein in vaalvon ke upayog ne anek kathinaaiyon evam samasyaaon ka niraakaran kar diya. isi ke lagbhag ek varsh ke hi anantar li di faurest ne traayod vaalv (triode valve) ka pranayan kar, electronic tatha radio sanchaar pranaali ke kshetr mein kraanti ka aavirbhaav kar diya. ye vaalv tatha inke anek sanshodhit roopon yatha tetrod (tetrode) evam peintod (pentode) aadi vaalvon ko hi radio sanchaar pranaali ko aadhunik roop tak pahuainchaane ka shreya diya ja sakta hai. pravardhakon, sansoochakon evam samasvarit paripthon ki sanrachana karanevaale kanpitron (oscillators) ki rachana inheen vaalvon ki sahaayata se ki jaati hai.

radio sangraahi

radio sanchaar pranaali ka vah ang jo eriyl (entena) tak nirantar pahuainchaanevaali radio aavrutti oorja se vaanchhit ansh (sanket ya soochana) pruthak‌ kar grahan karta hai, radio sangraahi kahalaata hai. sabhi prakaar ke radio sangraahiyon ko moolat: nimnalikhit kaarya karne padte hain :

(1) varan,
(2) pravardhan,
(3) sansoochan arthaat‌ radio aavrutti ka dhvani aavrutti, ya shravyaavrutti (A. ef.) mein parivrtit karna,
(4) shravyaavrutti pravardhan aur
(5) dhvani punarutpaadan.

varan

entena par nirantar anek prakaar ke radio sanket pahuainchate rahate hain, jo sansaar ke vibhinn bhaagon mein sthit preshan keindron se preshit hote hain. sangraahi mein is baat ki upayukt vyavastha honi chaahiye ki vah kisi bhi kshan kisi vaanchhit sanket vishesh ka varan kar, use anya sanketon se pruthak‌ kar, grahan kar sake. is prayojan ki siddhi ke hetu sangraahi ki varan vyavastha mein anek prerakatvon aur sandhaaritron ka samaavesh hota hai. inmein se ekaadhik parivrtaneeya, ya char bhi hote hain. inheen prerakatvon evam sandhaaritron ke sanyog se samasvarit paripth ki rachana hoti hai. is paripth mein prerakatvon evam sandhaaritron ke maan is prakaar samanjit kiye jaate hain ki paripth ki aavrutti graahya sanket ki aavrutti ke tulya ho jaae. us dasha mein paripth ko ukt sanket ke liye samasvarit kehte hain. etadarth prerakatvon evam sandhaaritron ke maan nimnalikhit sootr ke anusaar niyat kiye jaate hain :

f = 1/2p (L C)^(1/2)

jahaaain (L) prerak ka prerakatv, (C) sandhaaritr ki dhaarita tatha (f) graahya sanket (tatha samasvarit paripth ki bhi) aavrutti hai. is prakaar samasvarit paripth keval usi aavrutti ke sanketon ka varan kar grahan karta hai jo usaki aavrutti ke tulya hain shesh ko chhaaaintakar vilg kar deta hai. achhe sangraahi sanyantron mein aise kai paripth shreni kram mein sanyojit kiye hue hote hain jinse sangraahi ki varanasheelata, ya varanashakti paryaapt roop se sanvardhit ho jaati hai.

radio aavrutti ka pravardhan

entena se praapt radio sanket atyant ksheen hote hain. is kaaran ve laaudaspeekar ko kriyaanvit kar sakane mein asamarth rahate hain. at: unki shakti ko paryaapt pravardhit kar sakane ki kshamata sangraahi mein honi chaahiye. etadarth usamein pravardhan vyavastha sanyukt hoti hai.

sansoochan (Detection)

preshak keindron se sangraahi ke entena tak aanevaali sanketavaahini tarangein (carrier waves) atyant uchch aavrutti (radio aavrutti) ki hoti hain. isliye sangraahi mein pravisht hone ke pashchaat‌ inhein shravyaavruttiyon mein parint karna aavashyak hota hai. in shravyaavruttiyon ko pruthak‌ kar dhvanivistaarak mein pravisht karne ke pashchaat‌ hi sanket ko sun sakana sambhav hota hai radio tarangon ko dhvani tarangon mein parint karne ke hetu prayukt tantr-vyavastha ko sansoochak yukti (detector device) kehte hain

shravayaavrutti pravardhan (Audio-amplification)

sansoochak se nisrut shravyaavrutti sanketon ki shakti atyant ksheen hoti hai, jisse vah laaudaspeekar ko kriyaanvit kar sakane mein aksham rahati hai. at: laaudaspeekar mein pravisht hone ke poorv isko paryaapt maatra mein pravardhit karna aavashyak hota hai. is hetu prayukt vyavastha ko shravyaavrutti pravardhak kehte hain.

punarutpaadak vyavastha (Reproducer System)

shravyaavrutti sanketon ko vidyut‌ se dhvani mein roopaantarit karne ke liye laaudaspeekar ya shiraafon (headphone) bhi sangraahi set ka ek mukhya bhaag hota hai.

sangraahi ke prakaar

saral sangraahi (Straight Receiver)

ise samasvarit radio aavrutti sangraahi (Tuned Radio-Frequency, ya T. R. F., Receiver) bhi kehte hain. yeh sangraahi kisi vishesh radio aavruttiyon ke liye samasvarit (tyoond) rahata hai. iske andar sanvisht sabhi paripth vaanchhit radio aavruti ke liye ya to moolat: samasvarit rahate hain, ya unke saath aisi vyavastha sambaddh rahati hai ki aavrutti vishesh ke liye sabko ek saath samasvarit kar diya jaae. puraane dhang ke aise sangraahi mein aise pratyek paripth ke saath ek pruthak‌ samasvarak (tuning) sandhaaritr hota tha, kintu aadhunik seton mein ek hi parivrtaneeya, ya char (variable) sandhaaritr se sabhi paripthon ka is prakaar sanyukt kar diya jaata hai ki sandhaaritr ko ghumaane par uske bhinn bhinn dhaaritaansh maano se bhinn bhinn paripth jud jaate hain.

suparahetarodaain sangraahi (Superheterodyne Receiver)

vistrut lekh ke liye dekhein - suparahetarodaain sangraahi

pratham vishvayuddh ke dauraan major edavin Armstrong naamak vaigyaanik ne saral sangraahi mein apekshit sudhaar kar aisi sangraahi vyavastha ko janm diya jismein kisi bhi aavrutti ke sanket ko kisi samay sugamata se grahan kiya ja sakta hai. yeh vyavastha vastut: aadhunik lokapriya radio sangraahi seton ki janak hai.

svachaalit vaahanon mein prayukt honevaale radio sangraahi

svachaalit vaahan, jaise motor car, ya vaayuyaan ityaadi, mein prayukt radio sangraahi ke seton ki rachana saadhaaran gruhopayogi seton se thoda sa bhinn hoti hai. inmein shakti evam ooshma ke liye apekshit voltata vaahan ke chaalak baitari (starter battery) dvaara li jaati hai aur use abheesht aavrutti tak sanvardhit karne ke liye ek kanpitr (vibrator), ya ghoorni parivrtak (rotary converter) mein pravisht kiya jaata hai. is prakaar ke set ka eriyl ek patali dhaatu nalika hoti hai, jo car ke ek paarshv par, vaayuyaan ke daine par seedhi khadi lagaai jaati hai. is prakaar ke set ke naveenatam model ke samasvarak tatha vaulyoom niyantrak (volume control) steeyar dand (steering column) ke saath hi jade hote hain, jisse sangraahi ka sanchaalan suvidhaajanak dhang se kiya ja sake.

traanjistar sangraahi (Transistor Receiver)

1960 ke dashak ke ek radio ke andar ka drushya

radio sangraahi ko adhik upayogi, sasta tatha suvaahya banaane ke hetu vaalvon ke sthaan par traanjistar (transistor) ka upayog kiya jaane laga hai. yeh set keval saadhe chaar se chhah volt ki baitari dvaara chaalit hota hai tatha iski dakshata, arthaat‌ ise diye gaye tatha isse upalabdh shakti ka anupaat, saamaanya vaalv sangraahi ki apeksha chhah se das guna tak adhik hota hai. isse iska rakh rakhav vyaya vaalv traanjistar se 4 ya 5 guna kam hota hai. iske atirikt ye atyant laghukaaya, suvaahya evam saste hote hain. sugraahi to ye itne adhik hote hain ki ek saamaanya feraait chhad eriyl ki sahaayata se hi inhein kriyaanvit kiya ja sakta hai.

ekeekrut paripth vaale radio sangraahi

ekeekrut paripthon ke aa jaane ke baad ek hi I si (chip) ya kuchh chipon ki sahaayata se sasta, chhota, kam sel khaane wala aur achhi seva dene vaale radio sangraahi upalabdh ho gaye hain.