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I assume you mean why Q5 (pin 5) of the 4024 is connected to clock. I'm I'm not sure. Someone mentioned it may be a type of regenerative feedback on the forum I have this from. It's quite arbitrary I think. I've played around with the different outputs coupled with clock, also with different capacitors. The output tone will change and thermal stability can be slightly enhanced/weakened when doing this. Do

Do you mean 'no gold' as an extra indication literally (that would be ground breaking) or do you just mean 'no metal'? This circuit does actually have a background whine (high pitch as you call it) which I find annoying.

I will describe how this detector works out in the field, as I think you mayhavemay have a different picture of what goes on: Adjust

Adjust P1+P2 to the most sensitive point, just where the beeping stops.   
When metal gets close you get a slow beep-beep.   
The closer the metal gets the faster it will beep.   
The same happens when the temperature goes up (not as fast though).

What is new and very good here is the way this working point gets detected. It is the role of 4024 that forms a relaxation oscillator with narrow strip of input signal levels that brings it from non-operation to saturation, and in a process it provides a very sensitive indication. It operates on the oscillator's envelope rather than the DC level, pulse durations are set by pulse counting method, and in a process it provides pulsed audio.'

I assume you mean why Q5 (pin 5) of the 4024 is connected to clock. I'm not sure. Someone mentioned it may be a type of regenerative feedback on the forum I have this from. It's quite arbitrary I think. I've played around with the different outputs coupled with clock, also with different capacitors. The output tone will change and thermal stability can be slightly enhanced/weakened when doing this. Do you mean 'no gold' as an extra indication literally (that would be ground breaking) or do you just mean 'no metal'? This circuit does actually have a background whine (high pitch as you call it) which I find annoying.

I will describe how this detector works out in the field, as I think you mayhave a different picture of what goes on: Adjust P1+P2 to the most sensitive point, just where the beeping stops.  When metal gets close you get a slow beep-beep.  The closer the metal gets the faster it will beep.  The same happens when the temperature goes up (not as fast though).

What is new and very good here is the way this working point gets detected It is the role of 4024 that forms a relaxation oscillator with narrow strip of input signal levels that brings it from non-operation to saturation, and in a process it provides a very sensitive indication. It operates on the oscillator's envelope rather than the DC level, pulse durations are set by pulse counting method, and in a process it provides pulsed audio.'

I assume you mean why Q5 (pin 5) of the 4024 is connected to clock. I'm not sure. Someone mentioned it may be a type of regenerative feedback on the forum I have this from. It's quite arbitrary I think. I've played around with the different outputs coupled with clock, also with different capacitors. The output tone will change and thermal stability can be slightly enhanced/weakened when doing this.

Do you mean 'no gold' as an extra indication literally (that would be ground breaking) or do you just mean 'no metal'? This circuit does actually have a background whine (high pitch as you call it) which I find annoying.

I will describe how this detector works out in the field, as I think you may have a different picture of what goes on:

Adjust P1+P2 to the most sensitive point, just where the beeping stops. 
When metal gets close you get a slow beep-beep. 
The closer the metal gets the faster it will beep. 
The same happens when the temperature goes up (not as fast though).

What is new and very good here is the way this working point gets detected. It is the role of 4024 that forms a relaxation oscillator with narrow strip of input signal levels that brings it from non-operation to saturation, and in a process it provides a very sensitive indication. It operates on the oscillator's envelope rather than the DC level, pulse durations are set by pulse counting method, and in a process it provides pulsed audio.'

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For clarity (added later):For clarity (added later):

Questions answered/mor info:My replies to questions below with more info:

For clarity (added later):

Questions answered/mor info:

For clarity (added later):

My replies to questions below with more info:

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Questions answered/mor info:

I assume you mean why Q5 (pin 5) of the 4024 is connected to clock. I'm not sure. Someone mentioned it may be a type of regenerative feedback on the forum I have this from. It's quite arbitrary I think. I've played around with the different outputs coupled with clock, also with different capacitors. The output tone will change and thermal stability can be slightly enhanced/weakened when doing this. Do you mean 'no gold' as an extra indication literally (that would be ground breaking) or do you just mean 'no metal'? This circuit does actually have a background whine (high pitch as you call it) which I find annoying.

Yes, the power absorption raises the current. I only have to adjust the pots when temperature has changed.

I will describe how this detector works out in the field, as I think you mayhave a different picture of what goes on: Adjust P1+P2 to the most sensitive point, just where the beeping stops. When metal gets close you get a slow beep-beep. The closer the metal gets the faster it will beep. The same happens when the temperature goes up (not as fast though).

Here's a more technical quote about this probe I found on the forum I got the schematic from:

'Tr1 forms a Hartley oscillator and it is biassed so that it operates in linear regime that is prone to amplitude changes. When a metal object is introduced to the coil, the amplitude of oscillation is reduced because of the eddy current losses, but more importantly, the transistor power consumption is enlarged, and thus the emitter voltage gets shifted. This arrangement is not new, and most pinpointers work at this or similar principle. The change in the oscillator working conditions is translated into some sort of indication.

What is new and very good here is the way this working point gets detected It is the role of 4024 that forms a relaxation oscillator with narrow strip of input signal levels that brings it from non-operation to saturation, and in a process it provides a very sensitive indication. It operates on the oscillator's envelope rather than the DC level, pulse durations are set by pulse counting method, and in a process it provides pulsed audio.'

Questions answered/mor info:

I assume you mean why Q5 (pin 5) of the 4024 is connected to clock. I'm not sure. Someone mentioned it may be a type of regenerative feedback on the forum I have this from. It's quite arbitrary I think. I've played around with the different outputs coupled with clock, also with different capacitors. The output tone will change and thermal stability can be slightly enhanced/weakened when doing this. Do you mean 'no gold' as an extra indication literally (that would be ground breaking) or do you just mean 'no metal'? This circuit does actually have a background whine (high pitch as you call it) which I find annoying.

Yes, the power absorption raises the current. I only have to adjust the pots when temperature has changed.

I will describe how this detector works out in the field, as I think you mayhave a different picture of what goes on: Adjust P1+P2 to the most sensitive point, just where the beeping stops. When metal gets close you get a slow beep-beep. The closer the metal gets the faster it will beep. The same happens when the temperature goes up (not as fast though).

Here's a more technical quote about this probe I found on the forum I got the schematic from:

'Tr1 forms a Hartley oscillator and it is biassed so that it operates in linear regime that is prone to amplitude changes. When a metal object is introduced to the coil, the amplitude of oscillation is reduced because of the eddy current losses, but more importantly, the transistor power consumption is enlarged, and thus the emitter voltage gets shifted. This arrangement is not new, and most pinpointers work at this or similar principle. The change in the oscillator working conditions is translated into some sort of indication.

What is new and very good here is the way this working point gets detected It is the role of 4024 that forms a relaxation oscillator with narrow strip of input signal levels that brings it from non-operation to saturation, and in a process it provides a very sensitive indication. It operates on the oscillator's envelope rather than the DC level, pulse durations are set by pulse counting method, and in a process it provides pulsed audio.'

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