SBG- slow motion metal detector

[TurkAlperenebeg]

I'm sorry, I didn't know that.

[TurkAlperenebeg]

Hello! I am a 12th grade student at a technical school in electronics. We noticed discrepancies between the board and the schematic diagram, especially in the generator part. There, the two capacitors in the bases must be short-circuited, otherwise the transistor mode will not allow generation. We have not checked the board in detail, in this regard we trust you. Some annotations on the picture of the diagram I sent are details - to identify potentiometers, switches and others that will be placed on the front panel. Thank you very much for your interest! All the best! After I construct the device, I will send you a review

[scs-bg]

This is the final version with verified element values. There was only one difference - the resistors in the generator R2 and R13 have a value of 4.7 kilohms. One end of C7 is to minus. The generator works great. If you short-circuit the capacitors C1 and C8, it will not work with these resistor values. The circuit provides a small current through the transistors when the coil is not turned on.
I wish you success.

[scs-bg]

TurkAlperenebeg
Junior Member

• Join Date: May 2026
• Posts: 13

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#122
Today, 06:41 PM


Hello! I am a 12th grade student at a technical school in electronics. We noticed discrepancies between the board and the schematic diagram, especially in the generator part. There, the two capacitors in the bases must be short-circuited, otherwise the transistor mode will not allow generation. We have not checked the board in detail, in this regard we trust you. Some annotations on the picture of the diagram I sent are details - to identify potentiometers, switches and others that will be placed on the front panel. Thank you very much for your interest! All the best! After I construct the device, I will send you a review







Dear friend, electronics is a complicated thing and nothing is done there with assumptions or beautiful drawings. If you short-circuit the capacitors, the voltage on the bases of the transistors will be about 0.4 volts and they will be blocked. You are still young, you will learn many more things. I wish you to become a good specialist.

[ivconic]

No harm done, pcb remains the same:

[ivconic]

My pcb is on the way, it'll take 10-15 days to arrive.
This is just one testing pcb done by my colleague from China.

[ivconic]

[scs-bg]

This is the generator in reality. I took a picture so that there are no disputes and doubts. I am not angry with the young man from Turkey. No one knows everything when he is a beginner. He should not rush without checking everything. In the schemes, every detail is important. I have good friends from Russia and Turkey. They are people with great potential.

[ivconic]

My (AI) caricatures should not be taken seriously but only as a humorous illustration.
I'm currently in the "crazy AI drawing" phase.
This is a temporary state, I'll go back to normal when I get bored of AI drawing!

[ivconic]

But the greater wisdom of life lies in the simple fact; who does not inhale a lot of white smoke - he will never learn Electronics enough!

[pechkata]

This is the generator in reality. I took a picture so that there are no disputes and doubts. I am not angry with the young man from Turkey. No one knows everything when he is a beginner. He should not rush without checking everything. In the schemes, every detail is important. I have good friends from Russia and Turkey. They are people with great potential.

Yes, it's a very good oscillator - but it's a sequential oscillating circuit.
There is an air-ground difference.
He's good at the beach.

[pechkata]

First steps.

[pechkata]

https://www.youtube.com/shorts/FUa8om4co3A




80 volts peak.

[pechkata]

This scheme.

[scs-bg]

It doesn't matter whether the resonance is sequential or parallel. I hope you know what K factor is. I'm not going to become a teacher. Many fortune tellers have appeared on this forum. I don't want to deal with fables. In Bulgaria, everyone is competent in computers, women, brandy, politics and metal detectors. Do what you like. But first do, and then teach people!