TECHNICAL CHARACTERISTICS:
Stabilised tendency of catering: Vcc=9~12V
Frequency of reception: 88~108MHz
Consumption: 100mA
Materially:
The resistances are 1/4W.
R1
47K
R2
22K
R3 100K
R4
39K
R5
10
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
IC2
LM7805
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
REGULATIONS:
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.)
Source: Electronics Lab
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