Lrl from Italy

[kiro077]

For C2-C3-C3 I used the parasitic capacitance of the board. For C13-C14 (470pf). I use one printed circuit board for the whole lrl.

[FrancoItaly]

Originally Posted by kiro077

For C2-C3-C3 I used the parasitic capacitance of the board. For C13-C14 (470pf). I use one printed circuit board for the whole lrl.

As I told you, a PCB just for the sensor stage, with the bottom face connected to ground, makes a higher gain possible.

[FrancoItaly]

Originally Posted by FrancoItaly

As I told you, a PCB just for the sensor stage, with the bottom face connected to ground, makes a higher gain possible.

If there are many electromagnetic disturbances inside the house it is better to calibrate outside, also remember that the antenna must be connected during these operations, I recommend extending it to about 40cm.

[kiro077]

If I shield the box, will it get more amplification?

[FrancoItaly]

Originally Posted by kiro077

If I shield the box, will it get more amplification?

it is possible, in fact the body participates in the detection process, holding it with two hands the gain increases compared to holding it with just one hand, furthermore the lrl remains less sensitive to disturbances, it must be shielded (with aluminium foil, including the handle).

[osman34]

Originally Posted by omar

Yes, my friend Othman, there is a problem. Correct the location of the 33 nano capacitor connected to the 4148 signal correction diodes...


Note: Try the device with or without the protection diode on the voltage input and choose the best.

Merhaba Omer, I disabled the diode. I made a direct connection. How should I correct the positions of the 33 nano capacities?

[omar]

[FrancoItaly]

Originally Posted by omar

Both diodes are needed, they constitute a full wave rectifier, since silicon diodes have a conduction threshold of about 0.7V and signals lower than this threshold are blocked. However, this is not a problem since the signals are of higher amplitude.

[osman34]

Omer, first of all, thank you. I corrected the mistake I made. I am operating it with DC 18V supply, the buzzer is constantly beeping. The adjustable resistor only lights up the first Yellow LED and then the Blue LED. The Green LED close to the 7812 Regulator does not light up at all. I need to pay a little more attention.

[osman34]

Originally Posted by osman34

Omer, first of all thank you. I have corrected the mistake I made. I am operating it with DC 18V supply, the buzzer is beeping continuously. The adjustable resistance only lights up the first Yellow LED, then the Blue LED and the Green LED. When I touch the antenna point I do not get any response. Do you have any idea where I should check?

.

[okantex]

Dear osman34
How is istanbul?

Probably you have problem with your second lm358
Since first LED works, you should have Signal at entrance leg3 of second lm358. But both leds are not works..seems problem is on lm358.
Maybe burned..or maybe miss connection..check solderimg.