Midget medium-wave receiver
Published in issue 286, March 2000
The tiny medium-wave (MW) receiver described in this article is an ideal construction project to while away the dreariness of a rainy winter’s day. Solder a couple of standard components onto a tiny printed-circuit board, connect the finished board to a battery, and Bob ’s your uncle. Nowadays there are few construction projects or, indeed, commercially available equipment, that use discrete components only. Most apparatus encountered today has at least a processor and/or a number of integrated circuits. Although such equipment has the great advantages of reliability and simplicity, some readers may find the present project in which they can potter about without running into great difficulties a welcome surprise.The midget radio receiver consists of five common-or-garden transistors, one inductor and a handful of standard passive components. Most readers may well find that they have all the necessary components to hand.
Resistors:
R1 = 1MΩ
R2 = 1kΩ5
R3,R7 = 1kΩ8
R4 = 2MΩ2
R5 = 10kΩ
R6 = 560kΩ
R8 = 220Ω
R9 = 5kΩ6
P1 = 50kΩ linear potentiometer
P2 = 50kΩ logarithmic potentiometer
Capacitors:
C1 = 470pF
C2,C3,C4,C7 = 10nF
C5,C6 = 1µF 16V radial
C8,C9 = 220µF 16V radial
C10 = 100µF 63V radial
C11 = 100nF
Inductor:
L1 = 50 turns 0.3mm dia. (SWG30) enamelled copper wire on ferrite rod (10x100mm)
Semiconductors:
D1 = BB509 *
D2,D3 = 1N4148
T1 = BF245C or BF256C
T2,T3 = BC550C
T4 = BD140
T5 = BD139
Miscellaneous:
K1 = 3.5 mm jack socket
S1 = on/off switch
Bt1 = 9-V battery with clip-on connector
Ls1 = earpiece, headphones or 8Ω loudspeaker Enclosure: e.g., Conrad Electronics 52 09 93 (123x30x70mm)
PCB, order code 000034-1
|
Click below to download a PDF copy of this article from Elektor magazine. Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
|
Books
Password forgotten?
)
