Stiati ca..? In electronica, un "choke" este un inductor utilizat pentru a bloca frecventele mari la trecerea curentului continuu (DC) si frecventele joase la trecerea curentului alternativ (AC) intr-un circuit electric? Un "choke" consta, de obicei, dintr-o bobina de sarma izolata infasurata adesea pe un miez magnetic sau de ferita.
Ce prezinta cartea?
Cele 125 de circuite cu un singur tranzistor prezentate in aceasta carte sunt utile electronistilor amatori si nu numai. In carte sunt folosite doar cateva exemple de tranzistori ieftini; cu toate acestea, sunt reprezentate toate tipurile: germaniu, siliciu, NPN, PNP, unijunctiune si FET. Cititorul ar trebui sa poata configura si testa aceste circuite cu un efort si un echipament minim.
Proiectele circuitelor iau in considerare raspandirea relativ larga a valorilor tranzistorului; au fost utilizate valorile tipice ale producatorilor (sau unde au fost specificate numai valorile maxime si minime, a fost utilizata valoarea minima).
Astfel, unde este un rezistor de 30K specificat, o alegere intre valorile EIA standard de 27K si 33K poate fi indicata si poate fi necesar sa incercati ambele valori pentru a determina care functioneaza cel mai bine. Cu toate acestea, in cazul retelelor RC care determina frecventa, trebuie utilizate valorile exacte afisate. Urmand aceste instructiuni, cititorul ar trebui sa aiba mici probleme la duplicarea sau imbunatatirea performantei dorite.
Aceste circuite sunt oferite studentului care doreste sa configureze si sa testeze circuite tipice cu instructiuni proprii, proiectantului care doreste blocuri functionale gata facute pentru a fi incorporate intr-un sistem si hobbyst-ului ale carui interese amatorice vor fi deservite de circuite prestabilite, pretestate.
Structura cartii
CAP I – AUDIO AMPLIFIERS
Germanium common – emitter amplifier Silicon common – emitter amplifier Degenerative common – emitter amplifier Transformer – coupled common – emitter amplifier FET Common – source amplifier Emitter follower (divider biased) Emitter follower (resistor biased) FET source follower Headphone amplifier Microphone handle preamplifier Driver for Class B stage Five – watt power amplifier Phase inverter Audio mixer Gated amplifier Tuned – transformer bandpass amplifier Inductor – capacitor – tuned bandpass amplifier Inductor – capacitor – tuned bandstop amplifier RC – tuned bandpass amplifier RC – tuned bandstop amplifier
CAP II – RF, IF & DC AMPLIFIERS
Broadcast band RF amplifier (preselector) Conventional 455 kHz IF amplifier Single – tuned 455 kHz IF amplifier FET 455 kHz IF amplifier DC voltage amplifier DC current amplifier (low-level type) DC current amplifier (power type) Wideband (video) amplifier DC source follower DC emitter follower
CAP III – OSCILLATORS
Transformer – tuned AF oscillator (PNP) Transformer – tuned AF oscillator (FET) Hartley – Type AF oscillator Phase – shift RC audio oscillator Light – operated AF oscillator Self-excited RF oscillator Conventional crystal oscillator Pierce crystal oscillator Multi – frequency crystal oscillator Self-excited 100 – kHz oscillator Crystal type 100 – kHz oscillator Power AF oscillator Beat frequency oscillator (BFO) Micropower AF oscillator Carrier – operated AF oscillator Pulse – generating oscillator Relaxation oscillator Multivibrator TV sound -channel marker oscillator Self – modulated RF oscillator
CAP IV – CONTROL AND ALARM DEVICES
Sensitive DC relay (NPN) Sensitive DC relay (PNP) Sensitive DC relay (FET) Heavy-duty DC relay All-solid-state DC relay AC / RF relay Tuned AF relay Photoelectric Relay (solar-cell type) Photoelectric relay (photofet type) Heavy-duty photoelectric control (all solid-state) Temperature – sensitive relay Touch-plate relay Coincidence relay Coincidence switch ("and" circuit) Signal inverter Heater control (manual adjust) Audible alarm Visual alarm (lamp flasher) Carrier – failure alarm Interval timer Phase shifter
CAP V – TEST INSTRUMENTS
DC microammeter (NPN) DC microammeter (PNP) Electronic DC voltmeter General-purpose field -strength meter TV field-strength meter Dip oscillator (PNP) Dip oscillator (FET) Dip adapter AF frequency meter Audio signal injector Step – type audio oscillator Inductance / capacitance checker LC charts RF signal comparator Static detector (electrometer) Harmonic amplifier for frequency standards Electronic load resistor (PNP) Electronic load resistor (NPN) Heterodyne frequency meter AF signal-tracer adapter for VOM Phone monitor CW monitor DC voltage calibrator Electronic thermometer Sensitive absorption wavemeter AF wattmeter Tuned AF analyzer Metronome Bright-bulb stroboscope Sensitizer for DC milliammeter Circle generator for oscilloscope wheel patterns
CAP VI – POWER SUPPLY APPLICATION
Variable DC power supply DC voltage regulator (shunt type) DC voltage regulator (series type) DC to DC inverter (low voltage) DC to DC inverter (medium voltage) DC to DC inverter (high voltage) DC supply for tunnel diodes Constant current adapter (low level) Constant current adapter (high level) Electronic filter "choke"
CAP VII – RECEIVERS, TRANSMITTERS & ACCESSORIES
Simple broadcast receiver Diode receiver with transistor AF amplifier Step-tuned broadcast receiver Selective broadcast receiver Regenerative broadcast receiver All-wave regenerative receiver Autodyne converter Sun-powered broadcast receiver Meter-type tuning indicator Light-bulb type tuning indicator CW transmitter Frequency doubler Light beam receiver Code practice oscillator
Excelenta carte pentru incepatori. In denumire ati omis cuvantul 'One'. Seamana cu "Un tranzistor, doua tranzistoare" din Colectia Cristal (Ed. Albatros), dar mult mai "bogata" in montaje, desigur..
Da, despre bobina din prezentare, am gasit in radio auto, pe alimentare, 2 metri de conductor de bobinaj de 0,5, pusa in doua si bobinata pe o bara de ferita, intrebarea era de ce asa, apoi am inteles ca se comporta ca un blocaj pentru semnalele alternative parazite care veneau prin alimentare de la bujii.
Excelenta carte pentru incepatori. In denumire ati omis cuvantul 'One'. Seamana cu "Un tranzistor, doua tranzistoare" din Colectia Cristal (Ed. Albatros), dar mult mai "bogata" in montaje, desigur..
S-a omis cuvantul 'One' pentru un titlu mai clar. Intr-adevar seamana cu "Un tranzistor, doua tranzistoare" scrisa de Ilie Mihaescu.
Da, despre bobina din prezentare, am gasit in radio auto, pe alimentare, 2 metri de conductor de bobinaj de 0,5, pusa in doua si bobinata pe o bara de ferita, intrebarea era de ce asa, apoi am inteles ca se comporta ca un blocaj pentru semnalele alternative parazite care veneau prin alimentare de la bujii.