FM radio (may be used with PC) Schematic Circuit Diagram
The stabilized tendency of catering: Vcc=9~12V
The frequency of reception: 88~108MHz
[color=green]The resistances are 1/4W.[/color] R1 47K
R6-r12 7,5K – Optionally
R13-r21 15K – Optionally
P1 10K Logarithmic potentiometer
P2 100K Linear potentiometer
C1 39pF Ceramic
C2 47pF Ceramic
C3 2,2nF Polyester
C4, c14 220nF Polyester
C5 22nF Polyester
C6 10nF Polyester
C7, c18 180pF Ceramic
C8 150pF Ceramic
C9 100nF Polyester
C10, c13 330pF Ceramic
C11 220pF Ceramic
C12, c16 3300pF Ceramic
C15, c17 1800pF Ceramic
C19, c21, c22 10mF/16V electrolytic
C20 10nF Polyester
C23 47nF Polyester
C24, c25 470mF/16V electrolytic
L1, l2 5 Coils linked with internal diameter 4mm from cupreous isolated wire 0,6mm.
IC1 TDA7000 with base DIL18
IC3 LM386 with base DIL 8
D1 BB329 or BB105 or other than old tuner televisions.
SPEAKER Loudspeaker 8W/1W.
S1 Switch of catering.
AERIAL 50cm isolated wire
CONNECTOR DB25 Fastener of 25 pin parallel door PC (LPT) -Optional
A) With the P1 we regulate the intensity of sound.
B) With the P2 we regulate the frequency of reception.
C) Optionally: If you want to check the frequency with your PC it will be supposed you make the following energies:
– You assemble and the circuit that is in the blue frame.
– You cut the driver dj’pla in point A, as it appears in the circuit and you connect points A,V.
– If you know some language of programming as C ++, PASCAL, VISUAL BASIC, DELPHI etc you can write a program which will send in the parallel door (378 I) of PC a number from 0 until 255 checking thus the tendency of expense of simple D/A of converter (that it is in blue frame) and consequently and frequency of radio via passage VARICAP.
(As long as grows the number that sends in the parallel door, so much minimizes the frequency that receives the radio.)