Author Topic: Single coil latching relay help  (Read 7691 times)

electrosonic

Single coil latching relay help
« on: February 23, 2010, 04:04:09 AM »
On my last smallbear order I bought, a relay to mess with. (Panasonic TQ2-L-9V ) it took me a couple of hours to figure out that is not a dual coil latching relay thus the the Geo latching relay driver can't be used to drive it. Can anyone point me in the direction of a simple circuit using a momentary switch to drive this.

(Searching the forums brings leads me to this dead link, www.geocities.com/transmogrifox/relay
if anyone give me a copy to look at it I would appreciate it.)

Thanks,
Andrew.
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composition4

Re: Single coil latching relay help
« Reply #1 on: February 23, 2010, 04:56:23 AM »
About to go out sorry, but have a read of H-Bridges

http://en.wikipedia.org/wiki/H-bridge

can make one discrete wit transistors or buy them in packages

If you need more help, yell out and I'll discuss further tomorrow

R.G.

Re: Single coil latching relay help
« Reply #2 on: February 23, 2010, 11:44:31 AM »
This requires doing much what the latching relay circuit does, but pulling each side of the coil high/low as needed, and making that slow enough not to click at the same time. As noted, an H bridge driven by the slowing-down stuff should work, but it's about 2-4 times more circuitry than the two-coil latching stuff, and correspondingly trickier to get running.

It ... might... be cheaper to just take the price of the relay as a cost of education and reorder a double-coil-latching relay, depending on whether you want to learn about circuits or just get something to work.

Education is always expensive. Some times paying in money for it is the cheapest way. Depends on what you most want to happen.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

electrosonic

Re: Single coil latching relay help
« Reply #3 on: February 23, 2010, 07:44:36 PM »
What is the appeal of the single coil relay then? Is there any benefit to using them considering they are more work to use?

Andrew.
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R.G.

Re: Single coil latching relay help
« Reply #4 on: February 23, 2010, 11:01:49 PM »
The single and double coil relays are both useful. Which is most useful at the moment depends on what you already have. If what you have is a pair of signals that pulse for A or B, but are not otherwise related, dual coil is great. If you happen to have a pair of signals that always go in opposite directions already, the single coil is great. There was a trick with a SPST switch and a capacitor that made a single coil latching work, but I can't remember exactly what it was now. It's in the archive.

Both forms of signals - that is (a) separate up and down pulses and (b) complementary u/d and d/u signals - exist in different setups. The trick is to pick the relay which matches what you already have, or that you can derive most easily. Both pairs of signals contain the same information.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Processaurus

Re: Single coil latching relay help
« Reply #5 on: February 24, 2010, 01:19:10 AM »
On my last smallbear order I bought, a relay to mess with. (Panasonic TQ2-L-9V ) it took me a couple of hours to figure out that is not a dual coil latching relay thus the the Geo latching relay driver can't be used to drive it. Can anyone point me in the direction of a simple circuit using a momentary switch to drive this.

(Searching the forums brings leads me to this dead link, www.geocities.com/transmogrifox/relay
if anyone give me a copy to look at it I would appreciate it.)

Thanks,
Andrew.

I did that exact same thing!  Looked up the datasheet and everything, but it didn't register that they were single coil.  They don't seem particularly useful... except as a $7 lesson.

R.G.

Re: Single coil latching relay help
« Reply #6 on: February 24, 2010, 01:29:36 AM »
They don't seem particularly useful... except as a $7 lesson.
Man, I wish I could get my lessons for only $7 each!!   :icon_lol:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

theused69

Re: Single coil latching relay help
« Reply #7 on: April 25, 2010, 01:25:45 PM »
i need those relay driver schematics too, does someone still have a copy of those?

smallbearelec

Re: Single coil latching relay help
« Reply #8 on: April 25, 2010, 10:50:27 PM »
I apologize for the screwup. When I picked those parts to stock, I thought I was getting the ones needed to implement a circuit at GEO.

R. G.: If you will recommend an appropriate dual-coil part, I will order and send to those who suffered because I did not do enough homework.

SD

Processaurus

Re: Single coil latching relay help
« Reply #9 on: April 28, 2010, 07:29:07 AM »
I apologize for the screwup. When I picked those parts to stock, I thought I was getting the ones needed to implement a circuit at GEO.

R. G.: If you will recommend an appropriate dual-coil part, I will order and send to those who suffered because I did not do enough homework.

SD

Thanks very much, Steve!  The dog ate my homework on that count as well.  I'm currently using the orange NEC 5v latching relay, the EA2-5TNJ, from Mouser, based on RG's previous recommendation here on the series, and because they're $2.50.  NEC has a special 9v part but it seems harder to find and more expensive.  This one works wonderfully in the Geo circuit using a 130 ohm resistor in series with each coil, reliably down to a supply of 6 volts.

i need those relay driver schematics too, does someone still have a copy of those?

I couldn't find Transmogrifox's schematic anywhere, but the Geo one works, there's some discussion of it here:
http://www.diystompboxes.com/smfforum/index.php?topic=82010.0

smallbearelec

Re: Single coil latching relay help
« Reply #10 on: April 28, 2010, 10:47:37 AM »
I just saw this. Will order the dual-coil item. If you ordered the single-coil part, e-mail me and I will replace.

SD

Beo

Re: Single coil latching relay help
« Reply #11 on: October 09, 2011, 02:16:14 AM »
Does anyone have a copy of Transmogrifox's single coil latching relay circuit that they can post? Looks like his geocities page is gone, and he hasn't been active on the forum in a year.

Thanks,
Travis

bluelagoon

Re: Single coil latching relay help
« Reply #12 on: June 12, 2022, 01:03:48 AM »
The single and double coil relays are both useful. Which is most useful at the moment depends on what you already have. If what you have is a pair of signals that pulse for A or B, but are not otherwise related, dual coil is great. If you happen to have a pair of signals that always go in opposite directions already, the single coil is great. There was a trick with a SPST switch and a capacitor that made a single coil latching work, but I can't remember exactly what it was now. It's in the archive.

Both forms of signals - that is (a) separate up and down pulses and (b) complementary u/d and d/u signals - exist in different setups. The trick is to pick the relay which matches what you already have, or that you can derive most easily. Both pairs of signals contain the same information.

Thanks RG as always, for some great electronics guidance. There is a good article at the following web link to explain a low power relay switching scheme using a single coil latching relay such as the Panasonic TQ2-L-5V where it uses a capacitor charge , discharge to switch the single coil relay
https://www.freestompboxes.org/viewtopic.php?t=31684&start=200