5 pin Automotive Relay Use pins 87a and 87 as Common

Thread Starter

john2k

Joined Nov 14, 2019
207
I have a scenario where I have two power sources (one from parking light and one from ignition) and depending on whether the relay is energised or not, I want the relevant power source to be the output. So instead of using pin 30 as the common supply voltage, could I use pins 87a and 87 as the two different supplies and pin 30 as the output? I can't think why not unless a relay is one way or something
 

MisterBill2

Joined Jan 23, 2018
12,427
Both responses are correct. That is the benefit of using a mechanical relay. Solid state relays eor DC applications are usually polarity sensitive.
 

MaxHeadRoom

Joined Jul 18, 2013
25,469
I could I use pins 87a and 87 as the two different supplies and pin 30 as the output? I can't think why not unless a relay is one way or something
The relevant contacts are know as 30 = COM(on), 87a = N.C. , 87 = N.O. ( Normally-Closed/Normally- Open)
 
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