need adjustable voltage trip relay
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=135219
Printed Date: May 14, 2025 at 10:42 AM
Topic: need adjustable voltage trip relay
Posted By: jmyinc
Subject: need adjustable voltage trip relay
Date Posted: November 05, 2013 at 4:19 PM
I need some help from you guys! I'm working on a project that requires an adjustable voltage trip relay.
This will be used to control the electric lockers in a Ram Power Wagon. What I have is a knob with 3 positions. In position 1, I've got 0.9V on the output wire. Position 2 I've got 1.9V, and Position 3 I've got 2.7V.
I purchased the product below from ACI but I misread the description and it requires 24V and will not work on a 12V system. I landed all of my wiring and adjusted the pots and the LED's for each relay function perfectly, but there's not enough voltage there to trip the relays. What else can I do? I don't need anything that will handle a lot of current since all I am doing is triggering a separate 30/40A relay for each axle's locker.
https://workaci.com/products/aar-analog-input-2-adjustable-relay-outputs
Replies:
Posted By: oldspark
Date Posted: November 05, 2013 at 6:17 PM
Use a comparator. Typical single supply comparators are cheap ($1?) and available in quad packages. (eg - LM339 from memory.)
There are plenty of tutorials and circuit examples in webland.
Posted By: davep.
Date Posted: November 12, 2013 at 10:54 AM
Jameco Electronics has a 12 to 24 Converter for $22.95. Might be a simple / inexpensive way to make what you've already done work.
https://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_175813_-1
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