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Correct relay for my project...

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Renato

New Member
Hello all,

I am hoping that a correct relay will be able to help me with my project. I have tried 2 different relays and I can not get it to work... Also, I need to use the smallest possible 12 V DC relay. I have used Omron's G5A- relays.

Here is the scenario that I am trying to get working.

1) I need a relay that will take +- one time and the next time the signal will be -+. Polarity changes with each momentary signal.

2) I have 2 12V diodes, D1 and D2 that will be controlled by the relay. Once the relay is engaged it will turn on D1. The next time relay is engaged it will turn on D2 and turn off D1. The next time it is engaged it will turn on D1 and turn off D2. And so on...

Thanks you all for your help... Not even sure if this is possible.

Regards,
Renato
 

MikeMl

Well-Known Member
Most Helpful Member
This sounds like the sort of thing that used to be done with relays 50 years ago.
Today, most of us would do it with logic chips.

Why do you think you need relays?

Do the relays have to maintain their state with no other power applied (i.e. physically latching some kind of mechanical escapement)?

What kind of loads are the relays switching (besides themselves to create the flip-flop behavior)?
 

be80be

Well-Known Member
Your not going to do that with A relay it takes 2 of them to make that work
 

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be80be

Well-Known Member
They make a switch that when you power it it will flip-flop but it's rotary not a relay.
A relay goes back to it's resting state.
 

Renato

New Member
Thanks for all the info... As I am processing your responses here is the explanation of what I am trying to control.
I am building a control panel for my model railroad layout. I use KATO Unitrack switches which are DC switches that are controlled by 2 wires(black and red). To throw the switch you ned a momentary +- signal and then to throw the switch the other way you need a momentary -+ switch. It works just fine with a DPDT Center Off Momentary switch. Depending on which way I press the toggle it will control the track switch.

Because this is controlled by a momentary switch you never know the direction the track is going and this is where the relays and diodes come into play.

So, I thought that I could get a relay that will turn on a diode and turn off the other as I send the momentary signal, but the momentary signal changes polarity.

Also, I tried the BCD circuit (Bipolar Capacitor Discharge) but I get a lot of noise from the switch when it is thrown in one direction. If I could figure out the reason I am getting the noise from the coil in the track switch this might be the best way to go. Also, in this circuit I am using SPDT Momentary switch. Attached is the BCD circuit that I used.
 

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Leftyretro

New Member
It sounds like you need a single coil latching relay. It will change state with just a monetary application of DC voltage and will set or reset depending on the polarity on the applied DC voltage. The voltage can be left on also, monentary application of voltage is only a feature not a requirement of latching relays, your choice.

Here is E-bay listing for 2 5vdc single coil latching relays:

2 pcs 5 Volt Relay, Latching, 2 Form C (DPDT) AL5WNK - eBay (item 110354893606 end time Mar-19-09 16:20:09 PDT)

If you wire a resistor of 350 ohms in series with one of the coil terminals you can run it on 12vdc.

Lefty
 
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Renato

New Member
Thank you all for your help...

I was able to find a resolution to the BCD circuit so I will not need a relay to control my directional diodes.

The issue with the buzzing noise coming from the switches had to due with "dirty" DC power coming from my power supply. A simple addition of a capacitor fixed the problem.

Regards,
Renato
 
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