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..
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.