ADLINK PCI-7260 - Manual (Page 62)

52 Appendix
Test to confirm. Use a capacitor with a breakdown voltage of 200
to 300V. Use AC type capacitors (non-polarized) for AC circuits.
Diode Circuit
This circuit is suitable for DC application. The diode connected in
parallel causes the energy stored in the coil to flow to the coil in
the form of current and dissipates it as joule heat at the resistance
component of the inductive load. This circuit further delays the
release time compared to the RC circuit.
Device Selection:
Use a diode with a reverse breakdown voltage at least 10 times
the circuit voltage and a forward current at least as large as the
load current. In electronic circuits where the circuit voltages
reverse breakdown voltage of above 2 to 3 times the power
supply voltage.
Diode & Zener diode Circuit
This circuit is also suitable for DC application. Effective when the
release time i the diode circuit is too long.
Contact
Inductive
Load
Diode
Contact
Inductive
Load
Diode