One Transistor Radio - Here is a simple circuit for a one transistor Audion type radio powered by a 1.5 V battery and Transistor BC548 It employs a set of standard low- impedance headphones with the headphone socket wired so that the two sides are connected in series thus giving an impedance of 64 Q. The supply to the circuit also passes through the headphones so that unplugging the headphones turns off the supply Using an Audion configuration means that the single transistor performs both demodulation and ampli- fication of the signal. The sensitivity of this receiver is such that a 2 m length of wire is all that is needed as an antenna. The tap on the antenna coil is at l/5th of the total winding on the ferrite rod.The antenna coil on the 10 mm diameter by 100 mm long ferrite rod is made up of 60 turns with a tap point at every 10 turns; this is suit- able for medium wave reception. If a long external aerial is used it should be connected to a lower tap point to reduce its damping effect on the circuit. This circuit is suitable for reception of all AM transmissions from longwave through to shortwave.
Parts List :
Transistor BC548
R1 100K
VC1 500pF
C2 10uF
C3 100nF
L1 10mm diameter Coil, 100 mm long Ferrite rod
60 turns with a tap point 10 turns
Headphone 2 X 32 Ohm
Battery 1.5 V
Mini Box
PCB
Antenna Telescopic
Reference : Elektor Electronics - B.Kainka
No comments:
Post a Comment