Rough Science
Making a Metal Detector
To make your own metal detector, you will need:

1 1mH coil

2 1K resistors
2 1.5K resistors
1 6.8K resistor
2 220K resistors
1 1M resistor

1 220pf capacitor
2 10pf capacitors
10 4700pf capacitors

2 OA91 diodes
3 BC107B transistors
(note: BC107, 8 or 9 are the same)

1 tuning cap

1 crystal ear-piece

1 32 SWG wire

Wooden Dowel or a broom handle
A stiff piece of plastic (or a circuit board)
A plastic box to house the circuit
(and make it weatherproof)

9v battery
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