Question 1

Is there voltage on the com/nc/no from the DC+/IN side? I just need a signal wire with no voltage to connect when my 12v power source is enabled.

Accepted Answer

The com/NC/no is completely isolated from the DC+/In side.  You can use this relay to control your 12v power source.

Question 2

does the board have diode protection for the relay contacts in case of arc reversal from inductive loads switching off?

Accepted Answer

Absolutely NOT!   The "diode" protection on this board is standard, which is to say that it's across the COIL of the relay so that back EMF that such relay coils produce will not be imposed on the triggering circuitry.  Your question is with regard to relay contact protection which is a totally different thing. Manufacturers cannot put diodes across the contacts for this reason:  A diode placed across contacts that are wired to A.C. voltages will destroy itself.  Even D.C. will destroy the diode unless strict polarity is observed.   If you understand when a diode conducts and when it doesn't,  this will make sense.  When it comes to relays and back-emf protection, Google the subject. You'll see right away that protection diodes are wired across the COIL - never across the contacts themselves.  There are some good capacitor protection schema for the contact side of but this comes at a price -- not with these little module boards.   All that said,  I don't worry about these relay contacts. The whole module is cheap anyway. I would never press these into 10A service.  Personally, 5A-7A is my upper switching limit with these relays.

Question 3

Can this be triggered with trigger low and input from the n/o of another relay? when the other relay activates the n/o will be connected to ground

Accepted Answer

Voltage must go low to trigger. Example input normally 5vdc then goes to ground through a current limiting resistor.

Question 4

In the input there is dc+ and dc - what is the 3rd pin in for ?

Accepted Answer

The 3rd input is a signal, when you connect power to the 3rd input the switch in the relay becomes connected.

ASIN	B00LW15D1M
Best Sellers Rank	#186,055 in Automotive ( See Top 100 in Automotive ) #51 in Automotive Replacement Relay Control Module Relays
Brand Name	HiLetgo
Coil Voltage	12 volts
Connector Type	Terminal Leads
Contact Current Rating	10 A
Contact Material	Silver
Contact Type	Normally Closed, Normally Open
Current Rating	10 A
Customer Reviews	4.4 4.4 out of 5 stars (459)
Manufacturer	HiLetgo
Maximum Switching Current	10 A
Maximum Switching Voltage	250 volts
Minimum Switching Voltage	12 volts_of_direct_current
Model	3-01-0341
Mounting Type	Screw Mount
Number of Items	1
Number of Packs	1
Operation Mode	Automatic
Part Number	3-01-0341
Specification Met	Vcc
UPC	702082655955
Unit Count	1 Count
Wattage	120 watts

HiLetgo 12V 1 Channel Relay Module with Optocoupler Isolation Support High or Low Level Trigger

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