Toggle to Momentary Relay Output

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=146260
Printed Date: May 02, 2025 at 11:24 AM

Topic: Toggle to Momentary Relay Output

Posted By: kapp1
Subject: Toggle to Momentary Relay Output
Date Posted: June 07, 2020 at 1:27 AM

Hi
I have the need to convert an on/off toggle switch to a momentary relay output.
When the toggle switch changes from On - off - on (etc) a momentary pulse (1 sec or less) is required from the relay.
There must be no voltage on the relay output.
I would prefer to use a 12 volt relay on the input side

Thanking you in advance
KP

Replies:

Posted By: i am an idiot
Date Posted: June 07, 2020 at 7:23 PM

Do you need a pulse when off to on, and then the same when you turn it back off?

Posted By: i am an idiot
Date Posted: June 07, 2020 at 7:28 PM

This in conjunction
with this will do it

Connect both of the switched 12 v connections to the switch. Connect the 2 output connections to your device that needs the pulse.

Posted By: kapp1
Date Posted: June 08, 2020 at 12:47 AM

Yes iam after a pulse when a switch is turned on & another pulse when switch turned off.
it is for controlling model railway signals.

When I turn the switch ON - the relay buzzes & may/may not momentarily pulse the relay
When I turn switch OFF (ground) the relay pulses perfectly every time.

I have been using the following 12V SPDT 10A Relay:
- Rated voltage - 12V DC
- Coil current - 30mA
- Coil resistance - 400ohms
- Contact rating - 3 Amp-

Iam going to try 12V SPST Reed Relay
- Contact form: SPST normally open
- Coil Resistance: 1050ohms
- Nom Volts: 12
- Pickup Voltage: 8.4V DC
- Rated Current: 11.4mA