Capacitance Meter
using a CMOS timer
Materials
Gerber file
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Component list
R1 = 390?
R2 = 22M?
R3 = 2M?2
R4 = 220k?
R5,R9 = 22k?
R6 = 2k?2
R7 = 220?
R8 = 1k?
P1 = 2M?5 preset
P2 = 25k? preset
Capacitors:
C1,C2,C4 = 100nF
C3 = 10µF 63V radial
C5 = 47µF 16V radial
Semiconductors:
D1,D3 = zener diode 5V6, 500mW
D2 = LED, red, high-efficiency (2mA)
T1 = BF245A or BF256A
IC1,IC2 = 555C or TLC555 (CMOS 555)
Miscellaneous:
S1 = rotary switch, 2 poles, 6 positions
S2 = pushbutton, 1 make contact
K1,K2 = 4-way SIL socket for IC pins, turned pins
Case, 60 x 10 x 126 mm with battery compartment
Knob
Moving coil meter, f.s.d.100 µA
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