9
3051_1_Product_Manual - November 1, 2010
Wetting Current
When a relay is in one switch position for a period of time, oxidation of the open contact(s) can occur. Depending
upon the internal coating material of the contacts, oxide films of varying density will be displaced upon the surface
of open contacts; this film acts as an insulator to current flow. When the relay is switched, a certain amount of
current flowing through the contacts, known as the wetting current, is required to remove the film of oxides and
ensure proper conduction. Because of this requirement, these relays are not reliable for signal switching. See the
device specification on page 10 for detailed requirements.
Load Noise
If highly inductive loads are used with the Dual Relay Board, it is recommended that a noise limiting component be
used to prevent damage to the device. An MOV, TVS diode, or kickback diode (for DC applications) shunted across
the load will assist in dissipating voltage transients.
Analog Input Cable Connectors
Each Analog Input uses a 3-pin, 0.100 inch pitch locking connector.
Pictured here is a plug with the connections labeled. The connectors
are commonly available - refer to the Table below for manufacturer part
numbers.
Cable Connectors
Manufacturer
Part Number
Description
Molex
50-57-9403
3 Position Cable Connector
Molex
16-02-0102
Wire Crimp Insert for Cable Connector
Molex
70543-0002
3 Position Vertical PCB Connector
Molex
70553-0002
3 Position Right-Angle PCB Connector (Gold)
Molex
70553-0037
3 Position Right-Angle PCB Connector (Tin)
Molex
15-91-2035
3 Position Right-Angle PCB Connector - Surface Mount
Note: Most of the above components can be bought at
www.digikey.com
