Forgotten metal detector .. off resonance

[aft_72005]

Hello ...

... Does anyone have a circuit or circuits for this?
Is there a circuit published in old publications about this?

[profesor]

https://www.hobby-hour.com/electronics/s/cointrack-gd1190.php

[kt315]

this?

[aft_72005]

this?

Hi KT315
I don't know what type it

[aft_72005]

https://www.hobby-hour.com/electroni...ack-gd1190.php

but this is yes ... offresounance .

thank you .

is there are other schematic ?

[Carl-NC]

Pretty much all of the A.H. detectors (like A.H. Pro, Super Pro, Quintron, etc) were off-resonance. Here is the Pro schematic:


ITMD3 has a chapter on off-resonance design:

[DavidB]

One of the Heathkit models is off resonance. To much drift, works on the bench but even sun shining on the coil case makes it drift. Not really worth the time when there are better ways to do things.

[aft_72005]

Pretty much all of the A.H. detectors (like A.H. Pro, Super Pro, Quintron, etc) were off-resonance. Here is the Pro schematic:


ITMD3 has a chapter on off-resonance design:

Thank you for your guidance.