how to make a deep metal detector

Schematic & PCB:
https://drive.google.com/drive/folder...

Components and supplies:
220 ohm Resistor
1K ohm Resistor
47K ohm Resistor X3
100 ohm Resistor
10K ohm Resistor X2
47 ohm Resistor
10 ohm Resistor
390 ohm Resistor
68K ohm Resistor X2
1.8M ohm Resistor
120K ohm Resistor
470K ohm Resistor
1N4148 Diode X2
NE555 Timer IC
TL072 JFET dual operational amplifiers
10K Ohm Potentiometer
22K Ohm Potentiometer
1000uF, 16V Electrolytic Capacitor
1nf Ceramic Capacitor
100nF Polyester Capacitor X2
10uF, 16V Tantalum Capacitor X3
1uF, 16V Tantalum Capacitor
BC547B Transistor
BC557 Transistor
IRF740 Power MOSFET
2-Pin Screw Terminal Block Connector
On Off Single Pole Rocker Switch (Mini Black – 2Pin)
Passive Buzzer (12V)
1-Amp Electrical Glass Fuse
Mono Channel Headphone Jack Socket (3-Pin DIP)
GX16 2-Pin Round Shell Aviation Connector (Set of Male and female)
Copper Wire 0.8mm
Sealed Lead Acid Battery (12V / 1.2 to 4.5Ah)

Video parts list:
00:00 Schematic and PCB of the metal detector circuit
00:40 Assembling the metal detector circuit
09:30 How to connect the fuse to the metal detector circuit
10:17 How to connect the switch to the metal detector kit
10:38 How to connect the headphone jack to the metal detector kit
11:25 How to connect coil connector to metal detector kit
12:33 Training on making a coil for a metal detector kit
16:51 Battery connection to metal detector kit
17:15 Testing the metal detector circuit