Mains voltage zero crossing detector with optical isolated output

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=A0 =A0 =A0 ...Jim Thompson

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You can add another voltage source non-coherent with the 60Hz in series with John S's LTSpice file- it doesn't take but a few volts to make your 'circuit' jitter around by half millisecond or so. That's some ZCD. Unless you do something else, it's not worth more than about

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Any zcd will jitter if you add an incoherent source to the AC line signal, unless you use a bandpass filter or PLL or something. The voltage at the zero crossing is... wait for it... zero!

Quit whining and design something better.

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=A0 =A0 =A0 =A0 ...Jim Thompson

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For purposes of phase control, zero crossing refers to the fundamental component and not the interference that has no reliable characterization.

I think it requires a password for the shared area that's different from the account password.

Use this for the link:

(It's the one you posted earlier)

Ed

Does this work?

Dropbox is wonderful for private use, but it's a little tricky for public stuff.

If using triacs integrate how much you got this time and feed the error back next cycle.

Which brings me to a somewhat related question which has been bugging me for awhile. If anybody would like to take a look, I posted it in ABSE under a thread titled "HP 8116A reset circuit"

Yes!

Grant.

Given the jitter problem under discussion, that doesn't help. Most people just close a slow loop around the ultimate output.

Back in ancient times, we did do the raised-cosine ramp trick to linearize the transfer curve, namely make the gate timing vs loop error relation nonlinear to compensate for the sinewave shape. That helps control loops a lot.

OK, what I did was view the "public" image and copy the URL. That doesn't work with Dropbox. What I need to do is have it explicitely generate a "public URL", a separate step.

Grrrrrr.

Disco lighting from my past ;-)...

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Sez you.

You know, the idea of a zero crossing opto-coupler, if that is what you're trying to imply is to not allow it to switch on at any time until the Line side is at or near the base line, then, if the gate switch is present, it'll allow a turn on, other wise, what you have there, can simply fire off any time.. basically...

Jamie

What I get a kick out of is the "maybe you should try heading home"

Jamie

The output is a cmos-compatible, 60 Hz square wave that is aligned with the AC sine wave. Downstream logic can do whatever it wants with it.

It does what it does.

VCC | | 100K | +---+---- cmos logic out | | AC-------100K-----180nF------+----+ c | | | b === 1n | | e | A K ===> | | K A +---+ | | | | | | c | AC---------------------------+----+ b === 1n e | | | +---' | gnd

What do you call that, "A brainless hip shot" ?:-) ...Jim Thompson