4069 RG Keen latching relay driver

Started by njkmonty, July 25, 2014, 08:35:15 AM

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njkmonty

I have multiple breadboard projects running at present so excuse me for many threads

ive got the below mentioned layout  working ok , but trying to fine tune it.
im using a TQ2-L2-5V  relay, but just have a query about electrlytic c1  0.1uf
now i didnt have any electrolytics in that value  and just used a box cap. it worked  but appeared to be a bit volatile.
i grabbed the smallest electrolytic i had (2.2uf)  and seemed to work more to my liking, just wondering
is it meant to be a polarised cap? if so is the value critical?






R.G.

It's not critical. If you likd 2.2u better, go for it.

The voltage across it is always zero or greater in the direction toward the switch lead, so I think polarized is OK.
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.

johnk

I made a few of them with the Axicom relays and they work perfectly. I also have 10 of the Panasonic TQ2-L2-5V' but when it tried one of those in this circuit it doesn't activate the relay at all. the led goes on and off okay, but there's no relay switching. I wonder what's up with that?

R.G.

Don't know. The usual suspects come into play - wrong pinout, bad joints, incorrect interpretation of the relay datasheet and pinout, etc.

I would personally take the specific relay and see if I could trigger it by applying +5V to the joined + ends of the relay coils and connecting ground to the negative ends of the set and reset coils alternately. If it does that (you'll hear the click), I would test the output of the driver circuit to see if it's really set up correctly and the output of the CMOS chip was actually alternating, driver transistor collectors pulling to ground.

That is, go look at everything to see it's working right. Circuit like this, should take about ten minutes.
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.