Hey, actually figured something out on my own! (zero-crossing detector)

[TimFox]

I miss the animated Hamm's bear.

[Analog Kid]

We want a pulse on each zero crossing. Like what @Tooki drew:

(Attachment Link)

Why do we want that? What is an application where we need two pulses per period and cannot accomplish the same thing with the square wave?

I don't know.
I had a project in mind that needed this, can't think of it now.
Why don't y'all just humor me, consider this an interesting electronic challenge.
How could a guy generate short-ish pulses from that nice square wave at each zero crossing?
Surely you smart guys can come up with something.

[Analog Kid]

I miss the animated Hamm's bear.

[Indian drums: BOOM boom boom boom BOOM boom boom boom]

From the land of sky blue waters,
From the land of pines, lofty balsams,
Comes the beer refreshing—Hamm's, the beer refreshing.

[TimFox]

My favorite ad from that era has the bear playing hockey goalie and flirting with a cute lady beaver in the stands.
Her bratty kid-brother beaver chews a puck-clearing hole in his goalie stick.

[Analog Kid]

Apparently that beaver also owns a chainsaw:

[Circlotron]

Here’s one I cooked up many years ago. Used it quite successfully in SCR soft starters for three-phase induction motors.

[xvr]

Surely you smart guys can come up with something.

Once more???

https://www.eevblog.com/forum/beginners/hey-actually-figured-something-out-on-my-own

[Zero999]

That's only halfwave. Here's a fullwave solution, which is designed to work from a bridge rectifier.


EDIT: I attached the wrong .asc file. Here's the correct one.

[Picuino]

Very precise and robust detector from: http://web.archive.org/web/20170704120431/www.dextrel.net/diyzerocrosser.htm



FEATURES:
    highly accurate mains zero crossing detection
    fully isolated and low voltage safe output
    ultra-low power consumption; worst case power dissipation < 120mW
    produces symmetrical pulses around zero crossings
    output pulse stays constant, independent of the mains voltage
    very low parts count, no precision components required
    all components can be low voltage SMD
    works over all voltage ranges (100VAC/240VAC), without modification
    50Hz/60Hz compatible
    50Hz produces a 1ms ZC pulse, 60Hz produces 0.83ms ZC pulse
    highly stable with varying temperature and aging

[Picuino]

The only drawback I find to this circuit is that it is necessary to count only the even pulses (or odd pulses) to accurately measure the network frequency, because the time from an even pulse to an odd pulse is not the same as from an odd pulse to an even pulse.

[Analog Kid]

That's only halfwave. Here's a fullwave solution, which is designed to work from a bridge rectifier.

I loves it. Thanks!

Same old story here: I post a question, get a few answers, then the naysayers come out at night, accusing me of being a troll (!?!?!) but posting nothing of use.

Then someone posts a simple and elegant solution to my question. Which proves my theory that there are indeed people who not only know more than I do about electronics here, but who are willing to share their knowledge without condescension, carping or chiding.

Good job, @Zero999!

[xvr]

> but posting nothing of use.

I give up. Why you ask a question when don't want to see an answer?

[Analog Kid]

> but posting nothing of use.

I give up. Why you ask a question when don't want to see an answer?

Au contraire, mon ami.
I did want an answer, and I got it from comrade @Zero999.
OK?

What I don't want is a rash of shit saying "why bother asking that question?" or "what, are you nuts?" or things along those lines.

[xvr]

You got 3 answers in total, but ignore 2 of them

[Analog Kid]

You got 3 answers in total, but ignore 2 of them

That's because I only got one that provided the solution I asked for (pulses on all zero crossings).

[xvr]

Once again - you got 3 answers for your question - pulses on each edge of conparator output. And ignore (or didn't understand) 2 of them

[Analog Kid]

Once again - you got 3 answers for your question - pulses on each edge of conparator output. And ignore (or didn't understand) 2 of them

To be fair, @Circlotron did post such a solution, but it looked a bit too complex for my taste (4 op-amps!).
We are allowed to pick and choose which solutions we like, yes?
Or are now subject to CCP rules that mandate that we accept all solutions equally?

[xvr]

Post #19 and post #35 was ignored. Yes, you have a right take in account or ignore any solution on your choise, but don't be surprised to be taken as a troll in this case.

[Analog Kid]

I'm trying to simulate #19 in LTSpice. Unfortunately, can't seem to do it, as for some reason the program doesn't recognize some of its own models (trying to use CD4030 or CD4070, since I don't have any of the 74HCT models).

[Zero999]

That's only halfwave. Here's a fullwave solution, which is designed to work from a bridge rectifier.

I loves it. Thanks!

Same old story here: I post a question, get a few answers, then the naysayers come out at night, accusing me of being a troll (!?!?!) but posting nothing of use.

Then someone posts a simple and elegant solution to my question. Which proves my theory that there are indeed people who not only know more than I do about electronics here, but who are willing to share their knowledge without condescension, carping or chiding.

Good job, @Zero999!

This was suggested in post 8, all due respect to zero999

Just stuff the output of a bridge rectifier into the AoE design and you have what you asked for.

There have been several other perfectly sound suggestions all ignored.

If you want to discuss a topic, do so, but FFS stop weaving a bullshit story into it and keep dismissing those who try to help, making pedantic comments about their answers, spelling, prose and wasting their time.

You are a troll, just not a very clever one.

I was a little puzzled about why he preferred my design over the others. It's nothing special. Plenty of other sensible suggestions have been posted. My design has its downsides, the main one being that it isn't isolated, but that wasn't a requirement. I just wanted something which will work with a bridge rectifier and doesn't require an additional diode in series with the load, so the zero crossing circuit is isolated with the smoothing capacitor.

Perhaps it's because I included a clear simulation and plot?

[MrAl]

Here is a low parts count design.

Note you have to size the resistors according to the input line.
Also note that R8 and R9 may be needed to decrease the fall time because the 4N35 opto's are pretty slow.
There maybe a little phase shift (test that) so it also depends exactly how accurate you need to detect the zero crossing point.

I used the schematic from post #35 as a starting point for the drawing itself.

[Analog Kid]

This was my mistake not his (Analog Kid), as I didn't read whom the OP author was when first replying as I thought I had put the user on the ignore list so I didnt interact any more and get pissed at him.

Please, by all means do put me on your ignore list.
You're just a snob, and an unhelpful asshole to boot.

[Analog Kid]

Here is a low parts count design.

Note you have to size the resistors according to the input line.
Also note that R8 and R9 may be needed to decrease the fall time because the 4N35 opto's are pretty slow.
There maybe a little phase shift (test that) so it also depends exactly how accurate you need to detect the zero crossing point.

I used the schematic from post #35 as a starting point for the drawing itself.

Thanks.
My zero-crossing detector wouldn't need any line isolation like that.
If you wouldn't mind, could you tell us what the output waveforms look like? And how would we deal with the two separate outputs?

[Zero999]

Here is a low parts count design.

Note you have to size the resistors according to the input line.
Also note that R8 and R9 may be needed to decrease the fall time because the 4N35 opto's are pretty slow.
There maybe a little phase shift (test that) so it also depends exactly how accurate you need to detect the zero crossing point.

I used the schematic from post #35 as a starting point for the drawing itself.

I would just use an opto-coupler with an AC input, rather than two opto-couplers.
https://www.vishay.com/docs/83608/83608.pdf

Here is a low parts count design.

Note you have to size the resistors according to the input line.
Also note that R8 and R9 may be needed to decrease the fall time because the 4N35 opto's are pretty slow.
There maybe a little phase shift (test that) so it also depends exactly how accurate you need to detect the zero crossing point.

I used the schematic from post #35 as a starting point for the drawing itself.

Thanks.
My zero-crossing detector wouldn't need any line isolation like that.
If you wouldn't mind, could you tell us what the output waveforms look like? And how would we deal with the two separate outputs?

What are you talking about?  There is only one output. Take another look at the circuit.

[Xena E]

This was my mistake not his (Analog Kid), as I didn't read whom the OP author was when first replying as I thought I had put the user on the ignore list so I didnt interact any more and get pissed at him.

Please, by all means do put me on your ignore list.
You're just a snob, and an unhelpful asshole to boot.

Thank you! I did, but for some reason the forum started to display them again.

It's sorted now though.

I dont know why unhelpful? I suggested upthread that you just feed a bridge rectifier waveform into the AoE circuit and it's job done... but not realising it was you that was TS.

As you don't appreciate people being helpful, (don't understand, or have another agenda), I've saved you from reviewing my posts and have had them deleted in this thread.

Please accept my profound appologies for interupting your trolling.

Regards.
X (Dr Asshole)