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Transformerless power supply with only Live wire

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Thanks MrAl, now I got it.
Thanks RB, just bear in mind I am not so capable to do the circuit my own therefore I will need your help in terms of drawings, etc, like MrAl is helping me so far :)
Tomorrow I will get new optocoupler as the one I have is not responding anymore. There is a resistance when I measure the input diode in both directions so maybe I burned it.
 
Guys, this is the circuit of the PIR sensor:
image.jpg

If you say that is brilliant I can go to this one, trying to build the same for my project.
I cannot say much about it. I see a diac, somehow controlled by a diode, which on the other side is controlled by NPN transistor. 6 volts are powering the PIR sensor logic, that drives the transistor back.
The C1 is giving 19v and C2 is giving 6v - aways, no matter bulb state.
I am expecting your analysis and comments/ideas on that.
Cheers,
and have a great Sunday!
 
If you say that is brilliant I can go to this one
We would need to know all the component values to analyse the circuit properly :)
 
Why change the circuit?
 
Hi,
These are the components values:
image.jpg

And the PCB photo if it can help at all:
image.jpg

If you say it is good enough I could forget about the optocoupler and use this method with the transistor and the diac?
If you see a way to do it with optocoupler instead of this gate control great.
Actually I cannot say which method is better in this case.
I relay on your experience and knowledge.
MrAl, sorry I cannot get your last question.
Cheers!
 
Hello,

See drawing. I cleaned up the drawing a bit so that we can see the operation of the circuit a little more clearly.

I see a strange trigger circuit where it looks like the triac should be off when the transistor is turned on, but that might require values of R and C not within a reasonable range. Did you try this yet?
Why not use the relay?

The power supply section doesnt look too bad so far.
 

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Hi,
No I didn't try anything.
Just wanted to share the PIR sensor circuit if it can help.
Now I see in your editing there is no cap C4 anymore and now when the triac is on the rest will be shortened?!
You've put the Neutral going to the circuit but actually the Live goes out of the wall, the Neutral is in the ceiling to the bulb. If this matters at all. The sensor works no matter where is the neutral wire connected.
I don't get that with the relay. You mean relay instead of the triac or the relay from the receiver.
Btw i don't want to hear the relay :))
Thanks a lot for your time! Much appreciated.
Now what to do? :) I am a bit confused which is my next step/test.
Should i desolder everything and test step by step that circuit?
 
Hello,


First, where did you get the circuit with the transistor and diode to trigger the triac? That does not look like it works without unreasonable values for the capacitor.

Does your RF circuit have a relay output?
 
Hello,


First, where did you get the circuit with the transistor and diode to trigger the triac? That does not look like it works without unreasonable values for the capacitor.

Does your RF circuit have a relay output?

I took it from the PIR sensor I have. It detects motion and lights the bulb without neutral wire.
Therefore I wanted to investigate how it is done.
If you look at my previous posts, I've took several photos of this device.
Yes, the RF receiver comes with relay output.
 
Here is the circuit using the RF circuit. This should be tested.
 

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I took it from the PIR sensor I have. It detects motion and lights the bulb without neutral wire.
Therefore I wanted to investigate how it is done.
...

The PIR circuit (thanks MrAl for cleaning it up!) is based on a principle that I don't think you can use.

When the lights and TRIAC are OFF, the capacitive reactance supply produces enough voltage and current to run the PIR sensor and it's brain.

But once the lights and TRIAC turn ON, there will be very little available power from the cap reactance circuit!

With PIR controlled lights this doesn't matter because they use a "timed on period" which only needs a tiny bit of power. ie; the PIR device and brain etc don't need to be powered when the lights are on!

You needs are very different, as you need a rather high voltage and current (12v 30mA) at all times, even if lights are on.
 
Here is the circuit using the RF circuit. This should be tested.

Thanks a lot MrAl !
Now if that works would be great as the number of elements got less.
I will post in several days the test outcome as I am traveling on a business trip.
Meanwhile you or someone else if can explain in few words how the diac is doing the job would be great.
:) cheers!
 
Hello again,

The diac is a bilateral device that has a somewhat high resistance when off, and turns on by going to a lower resistance after a certain terminal voltage is reached. They come in various threshold voltages like 20, 30, etc. What this means to our circuit is that the triac wont be able to turn on until the line voltage reaches maybe 30 volts, and then it will come on because the diac will conduct. However, 30v on a line of 230vac means a delay of only around 250us, so we only have 250us to extract all the energy we need for the entire half cycle. That may not be enough so we might have to use a higher voltage diac or two in series. That's one of the reasons we have to test this.
Side note: Once the diac conducts if the line voltage is 30v and the DC power supply voltage is 15v, that really means we can only extract energy AFTER roughly 125us, so we really only have 125us left to extract all the energy we need for the entire half cycle. That's not much so we'll have to see how it goes and increase if needed. We cant go too high though or the bulb will start to dim.
 
...
With PIR controlled lights this doesn't matter because they use a "timed on period" which only needs a tiny bit of power. ie; the PIR device and brain etc don't need to be powered when the lights are on!

...

Actually this PIR have power 19V & 6V always (on the DC caps). Also, the PIR sensor is prolonging the ON time if the movement continues, i.e. it is not switching off always on exact time left. So this means it is monitoring non-stop, which means powered all the time.
 
Here is the circuit using the RF circuit. This should be tested.

I bought MOC 3052 optocoupler (Random Phase Optoisolator Triac Driver).
Here is the datasheet:
https://www.datasheetcatalog.org/datasheet/fairchild/MOC3052-M.pdf

The circuit they give I cannot understand very much because I cannot determine the resistor values for my case and because I cannot understand why is the transistor.
moc3052.png

Can I use this optocoupler insted of the diac circuit? Or forget about the optocoupler and get back to the DIAC thing.
 
Hello,

There's no reason to change the circuit at least not yet. You have to take the measurements next.
 
I agree. If the cap reactance supply can still provide the power rails when the TRIAC is on it likely has a delayed TRIAC firing (like we have been discussing).

We really need some scope measurements of the phase angle of the TRIAC firing when the lights are on.

And, just because that circuit can power the PIR brain (which may be low mA) doesn't mean it can provide the 30+ mA needed for the OP's desired circuit. :)
 
Hi,

I agree with MrRB.

Also, what is the rating for the RF module itself, as for current AND voltage? I forgot to ask that before.
 
Hi,

I agree with MrRB.

Also, what is the rating for the RF module itself, as for current AND voltage? I forgot to ask that before.

Hi,
The receiver is now at the Customs - I need to pick it up these days (after some holidays here till 8th of May).
Here is the link:
https://www.aliexpress.com/snapshot/227179294.html

BTW, I was able to connect the MOC3052 optocoupler, via full wave rectifier and zenner, and I was able to get 12V when TRIAC is off, and 5.6V when the bulb is ON. So I am basically done, except that I would appreciate if I had a bit more than 5.6V (the receiver needs 12V). When time I can share the components values.
/apologies but I have no access to the components right now... /

I guess it worked as the MOC3052 is a non-zero crossing IC - thanks MrAl for inlighting me on this matter. Thanks RB to you as well.
I will post what happend when I have the receiver in my hands and when back home.
 
Hello again,


You keep changing the circuit around and that's not helping. I have no idea what you are doing now because you changed the circuit and didnt post a new circuit drawing. Why did you decide to abandon the diac? If you want a different circuit that's fine but then why ask me?
 
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