Ok do i need higher than 1amp diode on this??

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=2724
Printed Date: August 06, 2025 at 6:40 AM

Topic: Ok do i need higher than 1amp diode on this??

Posted By: 2000vsm
Subject: Ok do i need higher than 1amp diode on this??
Date Posted: August 12, 2002 at 4:26 PM

Ok here

(12V+)----------[ | ]--------------SPDT RELAY 85 -----------86 --------ground

Diode cathode side is on the RIGHT

--------------->----->------> direction of current flow

is 1 amp too small here????????? also i see that 12volt here has diodes on the other side of the SPDT relay.. i assume they are using 1 amp diode and i'ts ok

Replies:

Posted By: sparkyssb
Date Posted: August 12, 2002 at 4:52 PM

probably not for a relay. you should be ok.

Posted By: 2000vsm
Date Posted: August 12, 2002 at 6:21 PM

you 100% sure?? what is the wattage rating of the coil of a 30/40 amp relay? (or tell me the resistance needed in the coil)

because i DO NOT want to pull out my wonderful wiring to change a few diodes here and there....

Posted By: omega
Date Posted: August 13, 2002 at 10:34 PM

I've never really seen more than 1 amp diodes used in car alarm installs myself...

1 Amp is fine. The typical current draw of a 30/40A, 12V SPDT relay is about 150-200mA, by the way.

Posted By: sparkyssb
Date Posted: August 14, 2002 at 12:54 PM

uh huh...

Posted By: 2000vsm
Date Posted: August 14, 2002 at 9:59 PM

car alarms maybe but doing other stuff like lights and ign.. you need 30 amp diodes...

btw.. the 6amp got hot and turned RED.... didn't work... i ended up using a relay... and i didn't ha've to change out the diodes since 150-200ma is ok...

lucky me

Posted By: omega
Date Posted: August 17, 2002 at 1:56 PM

6 amp? 30 amp? From the diagram it didn't indicate you were using it for lights or ignition! That's why I said 1 amp would be fine...

In the case of a high amperage circuit I would have definitely recommended relays.

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