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Zero beating Metal Detector

2014-11-14 00:29  
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Both oscillators are built using MPF102 or J310 FETs. The Mixer is BF998 dual gate MOSFET. Audio IC amplifier is LM386 which drives a speaker. I have used a stabilized supply for two oscillators and mixer. U1, a 78L05 is doing this job nicely. visit page.
Zero beating Metal Detector - img1
Circuit is being designed on a Single Sided Glass Epoxy Printed Circuit Board. It will be using PCB mounted volume control and a variable capacitor to tune the oscillator. (or varicaps & a pot) However, final design may change.You will have to wind the Loop Coil yourself. visit page.