Minimizing relay chatter using insulated rail for signals

If you are using DC power on a DC relay, I don't see how you can have any chatter.

I am using AC power to my relays via a bridge rectifier and I have no chatter....

Marty

Martin, it's easy to have chatter with DC if you don't have a filter cap on the power to the relay.  The wheels don't make a perfect contact many times until you get a few on the insulated rail.  It's very common to see the signal or accessory flicker when the train first enters the block.

Mark, the answer is yes, the caps should solve the problem.

 John, where would you put the filter cap? where across the positive lead of the relay and the output? In line with the positive? Just curious because I have many of these relays and will probably be doing the same thing

E-UNIT: The capacitor in this situation acts like a battery which charges from the inputs to the relay. Attach the capacitor using correct polarity to the inputs for the coil. (See illustration attached below).

-- Leo

Here's the deluxe way. This buffers the relay and also adds a choke for DCS compatibility.  This is how my signal board is done.

Here's what it looks like.

Thank you so much for posting this diagram. Will help a great deal.

If you're running conventional and the voltage may be low or off at times, you can power the "Center track" pin from an accessory transformer so the signals always work.

I will be using 12v dc as power source with the negative terminal tied to common ground. the relays I have draw 0.8 amps. how do you calculate resistor value?

thanks

Mark

.8 amps!!!   What kind of relays are you using???

Original post says coil is 120 Ohms … so 0.1 Amps at 12V.  0.8 A hopefully a typo?  Otherwise, yikes!

If using a 12V DC source resistor R1 is not necessary wrt '"Note 1".  But if GRJ is suggesting R1 to limit capacitor inrush current (possible wheel sparking) when charging C1, that's another story.   You only need Leo's circuit with "just" the capacitor - GRJ's circuit supports AC.

You are correct I meant 0.08 amps measured coil resistance at 135 Ohm. Sorry about that.