Fo rc e -S e n s e S w it c h e s
BALANCED 5-WIRE GUARD CIRCUIT
BASIC 3-WIRE GUARD CIRCUIT
DRIVEN GUARD
DRIVEN GUARD
(COAX CABLE SHIELD)
(COAX CABLE SHIELD)
GUARD AMPLIFIER
GUARD AMPLIFIER
SENSE
VOLTAGE OR
CURRENT
LEAKAGE
CURRENT
SENSE
VOLTAGE
OR CURRENT
LEAKAGE
CURRENT
VOLTAGE OR
CURRENT SOURCE
LEAKAGE
CURRENT
VOLTAGE OR
CURRENT SOURCE
3-WIRE GUARD CIRCUIT USING TRIAX
TRIAX CABLE
GUARD AMPLIFIER
SIGNAL
GUARD
GROUND
DRIVEN GUARD
(COAX CABLE SHIELD)
GUARD AMPLIFIER
SENSE
VOLTAGE OR
CURRENT
/MAX456
LEAKAGE
CURRENT
TRIAX CABLE/CONNECTOR
CENTER WIRE
INNER SHEILD
OUTER SHEILD
VOLTAGE OR
CURRENT SOURCE
Figure 2. 3-Wire and 5-Wire Guarded Measurements
16 ______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
