http://www.electroschematics.com/5921/m ... ld-sensor/http://www.electroschematics.com/796/ma ... eld-meter/Magnetic Field Meter Magnetometer Circuit
Circuit Parts list
Resistors:
R1, R9, R11*, R14 = 10 kOhm
R2*, R5, R7* = 1 kOhm
R3*, R6, R16 = 100 kOhm
R4, R8 = 1 MOhm
R10, R12 = 22 kOhm, 1%
R13 = 100 Ohm
R15 = 6.8 kOhm
R17 = 3.9 kOhm
R18, R19* = 39 kOhm
R20 = 82 kOhm, 1%
* = 1%
Capacitors:
C1, C7 = 100 µF, 10 V, radial
C2 = 10 nF, metallized polyester film, 5%
C3 = 4.7 µF, 10 V, radial
C4 = 10 µF, 10 V, radial
C5 = 47 pF
C6 = 2.2 µF, 10 V, radial
C8 = 100 µF, 16 V, radial
Inductors:
L1 = see text
Semiconductors:
D1-D3 = LED, green, high efficiency
D4-D6 = LED, yellow, high efficiency
D7-D10 = LED, red, high efficiency
D11 = 1N4148
Integrated circuits:
IC1 = TLC274
IC2 = LM3915
Miscellaneous:
S1 = single-pole switch with make contact
PC1-PC4 = soldering pin 1.3 mm dia.
Bt 1 = battery 9 V
Enclosure as suitable