# Triggering multiple relays with a single momentary switch

#### gsnow

Joined Aug 16, 2017
13
Full disclosure I'm a complete newb.

So I've spent hours googling my question and am surprised I can't find anything that seems to answer it.

How can I control nc/no status of multiple relays with a single momentary switch?

Thanks.

#### gsnow

Joined Aug 16, 2017
13
It's probably worth noting that they need to switch instantly and simultaneously. This is all low voltage. I'm still planning everything but I'll be somewhere between 5 - 12v. What I'm switching is not huge loads, if there's anything other than an audio signal on any of them it won't exceed that 5-12v range. I'm routing guitar signals around and would like to use relays to switch effects loops in and out simultaneously.

Thanks.

#### LesJones

Joined Jan 8, 2017
2,687
Just connect all the relay coils in parallel. No device switces in instantly. Relays will have switching time in the order of milliseconds. Electronic switches can switch in microseconds. You need to define your version of "instantly".

Les.

#### jayanthd

Joined Jul 4, 2015
904
Full disclosure I'm a complete newb.

So I've spent hours googling my question and am surprised I can't find anything that seems to answer it.

How can I control nc/no status of multiple relays with a single momentary switch?

Thanks.
Show your circuit. Maybe there is a simpler way to do it which use Digital logic and not using relays (which are slow switching devices ~10ms). If I clearly understand your needs then I might be able to design a circuit using digital logic ICs or a single micrcontroller.

#### gsnow

Joined Aug 16, 2017
13
Thanks for replies.

As for instantly, I guess I meant in terms of perception - I don't want a perceptible lag between them switching.

I know I don't want a microcontroller. I don't really want to reveal the entirety of my circuit. I just want a momentary switch to turn on multiple relays simultaneously with no perceptible lag. The relays will all switch either a low voltage or a guitar signals.

Thanks.

Joined Jan 15, 2015
5,621
Use a simple "latching" circuit and have the latching relay contacts energize your remaining relays with, as mentioned, the coils in parallel. Here is a rough example:

Use one set of N/O RY1 contacts to latch it and use another set to energize the remainder of your relays with the coils in parallel. Circuit voltage can be whatever you want. SW2 is a N/O pushbutton and pressing it will close the N/O contacts of RY1 "latching it" and pressing N/C SW1 will un-latch it, so you get an On & Off effect.

Ron

#### gsnow

Joined Aug 16, 2017
13
Thanks for the reply ron, but you seem to have added a momentary switch. Thats not going to work. I'm using 1 switch, not 2.

Thanks

#### gsnow

Joined Aug 16, 2017
13
It sounds like the main idea you guys are proposing is wiring the relays in parallel. This is precisely what I was googling and couldn't find much useful info, as this is precisely what my logic was.

So if I connect all their +v contacts to the same +v and then switch the - on and off via momentary switch this should cause all the relays to come on at the same time, correct?

There were a lot of implications that wiring relays in parallel was not a good idea in my Google results when I was searching, which is why I got so confused.

#### KMoffett

Joined Dec 19, 2007
2,899
gsnow,

So you want a momentary push-button, so one push latches the relays (or solid state equivalent) ON and a second push turns the relays off?

Ken

Added: parallel relays coils is a common practice.

#### gsnow

Joined Aug 16, 2017
13
I'll get them off. I shouldn't have included that word off in my previous post, just on.

I just want to focus on turning on multiple relays simultaneously with one push off a momentary switch.

#### gsnow

Joined Aug 16, 2017
13
I saw that you added to your post Ken. I believe parallel is what I need, I just couldn't find much confirming my logic when I googled so I wanted a little confidence that I wasn't barking up the wrong tree.

Thanks!

#### MrChips

Joined Oct 2, 2009
21,688
I would use analog switches instead of relays. Analog switches require much less power to control.

#### gsnow

Joined Aug 16, 2017
13
I'll have a look at them. Honestly in calculating the number of contacts I need to accomplish my goals relays may not be the most economical approach. I need a LOT of contacts.

Thanks

#### gsnow

Joined Aug 16, 2017
13
Hey mrchips

I've had a peek at the analog switches, again, newbiest of newbs here, but it seems like they can serve the same purpose as the relays would to me - the ability to switch something on and off.

Do you think you could help me narrow down what might be applicable to my needs?

Basically I need a ton of contacts. I'm thinking power supply in the 5-12v DC range if that matters. The contacts need to be able to carry those DC signals as well as guitar signals - so with the guitar signals preserving the level and integrity is paramount.
I don't know enough to know what else one might need to consider. I'm kinda piecing this together as I go. I know what I want my end result to be, I'm just trying to learn how to get there.

I don't mind reading, so if it's easier for you to point me to some literature I can follow up with any questions I have afterward. I will say I read a couple of the companies' guides on analog switches and I got a little bit out of it, but I'm not confident I'm fully understanding all of it.

#### MrChips

Joined Oct 2, 2009
21,688
You have to define "a ton".
How many contacts, 10, 16, 20, 100?

Lay out what you want to do. Switches, pushbuttons, control sequence (on-off controls), inputs, outputs. Draw a block diagram. Don't worry about circuit components at this stage. You can use the relay concepts but these will be replaced with analog switches. Common analog switches are CD4016 and CD4066. There are others you can also select. We need to see the design requirements first.

Don't switch power at this stage. That will complicate matters. Analog switches are meant to switch signals, not power. FX stomp boxes are usually powered by 9V PP3 batteries or 9-12VDC adapters.

Joined Jan 15, 2015
5,621
Thanks for the reply ron, but you seem to have added a momentary switch. Thats not going to work. I'm using 1 switch, not 2.

Thanks
The circuit was just an idea, the two PB switches are easily replaced with an On/Off switch and for that matter a simple On/Off SPST switch could energize all your relays with the coils in parallel. I can make you a cartoon (drawing) if you would like.

Ron

#### gsnow

Joined Aug 16, 2017
13
I have a block diagram, I am at the components stage.

I realize that I'm not doing anything that hasn't been done before, I just don't want all the details on such an open forum.

And probably close to 200 contacts.

#### gsnow

Joined Aug 16, 2017
13
Looks like the 2402 is obsolete. I'll look at those you mentioned

#### MrChips

Joined Oct 2, 2009
21,688
Have you priced how much 200 relays would cost? And how much power would be required to turn 200 relays on?

One 74HC4066SMD is about $0.25 and it contains four switches. That works out to about$0.06 per switch or \$12.50 for 200 switches.

#### eetech00

Joined Jun 8, 2013
1,967
Hi

If your switching guitar audio signals you might want to consider make-before-break contacts to avoid "pops or clicks" when the contact state changes.