81
A Appendix
1 Blue LED, ø 5mm
1 10-kOhm potentiometer (lin.) with switch
1 Turning knob ø 23mm
1 Piezo buzzer
1 9V battery clip
1 Hookup wire, 0.5m
1 Search coil 150 µH
Specications
Supply power: 9V
Current consumption: 9–15mA
Fig. A.1: Layout
