cFP-RLY-423
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Guidelines for Selecting Contact
Protection Circuits
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Proper selection is critical as the use of a contact-protection device
can extend contact life. When mounting the protection device,
always locate it near the immediate area of the load or contact.
Typically you should mount a protective device within 18 in. of
the load or contact.
Typical contact-protection circuits are shown here as an overview,
but you should thoroughly examine the circuit you are planning
to use.
Diode and Zener Diode Circuit
Diode Circuit
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This section has been reprinted with permission from American Zettler, Inc.
Diagram
Notes
Use in DC applications only.
Use when diode circuit causes too long
release time.
Use zener diode with zener voltage about
equal to power supply voltage.
Diagram
Notes
Use in DC applications only.
Compared to RC type, circuit delays release
time (2 to 5 times values stated in catalog).
For larger voltages, use diode with reverse
breakdown 10 times circuit voltage and
forward load circuit.
For smaller voltages, use reverse breakdown
voltage of 2 to 3 times power supply voltage.
Load
Load
