The value of R1, R2, C4, and C5 should be chosen in order to
keep at least 12V in Vs. Please connect C4 (>1μF) and C2 (<1μF).
ZCT and load resistance RL of ZCT are connected between input
pin 1 and 2. Protective resistance (RP=100Ω) must be insurted.
RL and amplifier’s output (in Pin 4) regulates sensitivity
current External capacitor C1 between pin 4 and GND is used for
noise removal. Please connect a varistor or a diode (2 pcs.) to
ZCT in parallel, because of when large current is grounded in
the primary side (AC line) of ZCT, the following situation can
be abandoned: The wave form in the secondary side of ZCT is
distorted and some signals do not appear in the output of
amplifier. Please connect capacitor (about 0.047μF) between pin
6 and pin 7. Capacitor C6 between pin 1 and GND is about 0.047μF
for removing noise. M54123L EARTH LEAKAGE CURRENT DETECTOR The
UTC M54123L is a semiconductor integrated circuit with amplifier
for a high-speed earth leakage circuit breaker. For the
amplifying parts of earth leak