IDEC MICRO3

1: GENERAL INFORMATION
USER’S MANUAL 1-17
Contact Protection Circuit for Relay Output
Depending on the load, a protection circuit may be needed for the relay output of the MICRO
3
. Choose a protection circuit
from A through D shown below according to the power supply and connect the protection circuit to the outside of the
MICRO
3
.
Protection Circuit A
Protection Circuit B
Protection Circuit C
Protection Circuit D
Inductive Load
COM
C
R
Output Q
This protection circuit can be used when the load impedance is
smaller than the RC impedance in an AC load power circuit.
C: 0.1 to 1 µF
R: Resistor of approximately the same resistance value as the load
Inductive Load
COM
R
Output Q
This protection circuit can be used for both AC and DC load power
circuits.
C: 0.1 to 1 µF
R: Resistor of approximately the same resistance value as the load
C
+
or
–
Inductive Load
COM
Output Q
This protection circuit can be used for DC load power circuits.
Use a diode with the following ratings.
Reverse withstand voltage: Power voltage of the load circuit × 10
Forward current: More than the load current
+–
Inductive Load
COM
Output Q
This protection circuit can be used for both AC and DC load power
circuits.
+
or
–
Varistor