Latched On/Off with momentary pulse

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=34175
Printed Date: August 25, 2025 at 6:57 AM

Topic: Latched On/Off with momentary pulse

Posted By: iG
Subject: Latched On/Off with momentary pulse
Date Posted: June 19, 2004 at 11:06 AM

hey.

I used the 5 relay setup for the latched on/off to build a circuit to power my computer..

When i first soldered everything together it seemed to work just great. However, after i did some testing today i ran into very interesting problems. When the power is cycled the momentary pulse turns on the circuit perfectly fine. However, cutting the power is another story! It only works every once in a while. If i sit there and keep sending it momentary pulses, eventually it turns off, otherwise I just hear the relays engage/disengage but constant 12V is still supplied. Occasionally when it does turn off, it powers up without a hitch. So the problem is cutting the power. I've checked the wiring a dozen of times, and everything seems to be fine.

Any ideas? I'm lost!

Replies:

Posted By: Mystikal_Dream
Date Posted: June 23, 2004 at 3:31 AM

I have to build this circuit and test it myself, but try this-connect a peice of wire to ground, and touch it to the circuits trigger input (basically bypass the switch, or just short out the switch). Try several different lenghts of time. Touch it very briefly, then touch it for a second or so. The problem might be that your momentary pulse does not trigger it long enough to cut the power. I am not sure of this, but thats all I can think of.

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Probe GT-Bepro!

Posted By: promodeepcycle
Date Posted: June 24, 2004 at 12:07 PM

25bucks =latching relay

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dont be a pet monkey ..use your dmm