Simple metal detector kit

PRINCIPLE FOR Simple metal detector kit:

Simple metal detector kit consists of a tuned colpitts oscillator and a switching circuit any ferrous materials brings the resonance circuit to be untuned , this untuning is sensor  by the transistor circuit to buzz a buzzer .

ADJUSTMENTS:

The value of presel resistor 4.7 k ohm has to be adjusted till the circuit  stops sounding inthe absence of any ferrous materials.

MAIN COMPONENTS:

sensing coil 2.547 NPN transistors

SKILL LEVEL REQUIREMENTS:

components identification

polarity identification

soldering

inductor winding

COMPONENTS REQUIREMENTS:

1.Copper coil

2.buzzer

3.9 volts battery cap

4.red led

5.NPN BC547  transistors

6.100 nano farad capacitors

7.100 micro farad 25 volts capacitors

8.10 k preset (pot)

9.resistors etc.