Hi all.
Been working on a metal detector project. I've come across quite a few schematics online.
I've tried to replicate the MKII by Talking Electronics: http://www.talkingelectronics.com/projects/MetalDetectorMkII/MetalDetectorMkII.html
Here is the Schematic:
However I have changed a few things due to availability and the circuit doesn't perform as expected.
I have used 1.25mm gauge fluxed wire forming 100mm diameter coils (According to the site the size of wire or coil isn't important)
I have replaced one of the BC547 transistors with a BC237
In place of "390R" surface mount I have used a 330R
When switched on I have observed the speaker voltage to be a constant 2.6V despite the position of the coils relative to each other or the position of the dial on the potentiometer - i.e no tone is produced on the speaker.
Any input will be appreciated
Been working on a metal detector project. I've come across quite a few schematics online.
I've tried to replicate the MKII by Talking Electronics: http://www.talkingelectronics.com/projects/MetalDetectorMkII/MetalDetectorMkII.html
Here is the Schematic:
However I have changed a few things due to availability and the circuit doesn't perform as expected.
I have used 1.25mm gauge fluxed wire forming 100mm diameter coils (According to the site the size of wire or coil isn't important)
I have replaced one of the BC547 transistors with a BC237
In place of "390R" surface mount I have used a 330R
When switched on I have observed the speaker voltage to be a constant 2.6V despite the position of the coils relative to each other or the position of the dial on the potentiometer - i.e no tone is produced on the speaker.
Any input will be appreciated