Tesoro Bandido - 18,5Khz - To find small gold nuggets

[Ruben2000]

Hi Andre, I would like to try this project. But I don't have the necessary instruments for the money. But I can start doing the PCB and I would like to know if the schematic you posted at the beginning is correct without errors to have it passed in Sprint.

[Ruben2000]

Sorry with my English I'm using a translator.

[bgs]

The oscillator of the circuit will not work because there is no positive feedback. I guess the circuit is not accurate.

[Andre]

The oscillator of the circuit will not work because there is no positive feedback. I guess the circuit is not accurate.

I don't want to create a discussion here. I just wanted to present my project to anyone interested in building. Pictures are worth a thousand words. If it is the absence of positive feedback enter the positive input. Place a 10M resistor to positively polarize this input.


The worst blind is the one who doesn't want to see!

[Andre]

[QUOTE = Ruben2000; 285932] Desculpe pelo meu ingl?s, estou usando um tradutor. [/ QUOTE]
Dear Ruben.
Thank you for your interest in my project. There are no interconnection errors between components. I noticed that the negative power supply of the U8 is showed as + Vdc. However, it is -Vcc (This is deductible). The success of the project is the components used and in the construction of the coil. There are many counterfeit components on the market. Be careful. I left the transmitter oscillator with variable frequency, precisely for experiments with the coils, to obtain greater performance. Unfortunately, an oscilloscope or a frequency meter is necessary for any type of project that involves oscillating signals.
As for your English translated automatically: Welcome to the club!

[Ruben2000]

Hi Andre, I am making a PCB in SPRINT and I have found some points that are not according to the diagram you have published. Here I send you some photos.
I would like you to clarify those points for me. Thank you very much Ruben2000.

[Ruben2000]

I'm in the middle of the PCB. Tomorrow I will continue with the rest.

[Op04]

LM79XX

Thanks Andre for providing this dual psu schematic, I like this way VS 7660 negative supply

[Andre]

Dear Op04,
The ICL766X causes ripples in the negative supply. So,. I don't like using it.
Thank you for message!

[Andre]

Ruben2000.

I found that resistance is not necessary. It was used to positively polarize the transistor base. You can also see that the U5 before was the LF353, now it is LF442. C10 is between pin 3 and pin 1. This went unnoticed.
Thanks for your comments!

[Andre]

Hi guys! As promised, this is the video of the modified 18.5 Khz Tesoro Bandido II air test. I don't have a genuine gold nugget, but the test of small pieces of 18 carat gold is shown here with good results. The smallest piece is less than 0.1g. The ring has 2g. The screw has 0.2g..
https://www.youtube.com/watch?v=KlQyRDzzqLM&ab

[bgs]

In order for the IC 7806 and 7906 to work, the difference between the supply and output voltages must be greater than 2 volts. You have 1.4 volts.

[bgs]

Gift -18 kHz oscillator

[Andre]

In order for the IC 7806 and 7906 to work, the difference between the supply and output voltages must be greater than 2 volts. You have 1.4 volts.

So, what is you see is a miracle of God!
Use 4.2V batteries and be happy!

[Andre]

Gift -18 kHz oscillator [ATTACH]54589[/ATTACH]

Congratulations for the theoretical complex circuit !