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Search the forum for Anand Dhuru's posts on building his own X10 modules for 230V. I believe he is using the hardware PWM to generate 120kHz. Also, Darrel Taylor made some modifications to the PBP XOut command that might be of use.Originally Posted by Dennis
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something odd ...
Hi all
Dave .. thanks once again for the extra info and tips :-) they always provide good reads and info :-)
Melanie,Steve and anoymouse...
While re-reading the Microchip appnotes, this one in particular
I noticed some interesting points...
Firstly this one regarding the current draw,
and then something strange about the FUSE on the NEUTRAL LINE ???The PIC12/16/17 microcontrollers draw a maximum of 10 mA, even at the highest frequency and voltage of operation, therefore low current availability is not an issue. AC line voltage isolation can be addressed by using MOVs or transient suppressors on the PIC12/16/17.
Any comments on these statements?In most applications, the output voltage should be reg-
ulated. Figure3 shows a diagram for a practical circuit
where a +/- 5V regulated output is generated. Note that
the neutral is connected to ground through a fuse. This
+5V
would guard against improper AC wiring.
Kind regards
Dennis
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Where did you get the second quote? The one about the neutral.
Have you checked your local electrical codes about the proper way to wire something for the system you have? Might clear up the neutral thing for you. Here the ground and neutral are "bonded in the box" not at the device. I can not see yours being any different, I am sure you have a transformer with a center tap providing power to you.
BTW, you never said why you want to do this or what you think the benefit will be.
Dave
Always wear safety glasses while programming.
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still researching ...
Hi Dave
Thanks for tip, I was going to get eyes in on the local sub-station but will do so tomorrow ;-) and update as soon as possible :-)
The quotation is actually from a Microchip appnote TB008 , the paragraph is just above figure 3. in the appnote. [HTML]http://ww1.microchip.com/downloads/en/AppNotes/91008C.pdf[/HTML]
Ok the project is for the PIR-sensor based security lights, I need to tap into the PIR and replace the existing LDR and sensor circuit which are also transformer-less and triac controlled. Each sensor light PIC transmit back to a central PIC.
Given the space I have I cannot fit a transformer based supply into the housing or wall point (someone did a good job installing them) and there is no way I can mount the circuit externally.
So transformer-less it is !
I have seen circuits aplenty on the web yet it seems most are common live and also mainly for 120VAC it seems.
Some even with dual fuses (one on LIVE and one on NEUTRAL!)
So it seems there is quite a lot of confusion in this arena and for good reason I suppose, fear of death being the ultimate reason people shy away and of course once bitten twice shy(being shocked into submission certainly shys people away).
So my quest was to research the topic of transformer-less supplies before I dive into anything like building one only to encounter serious injury and the possibility of my circuit frying !
Nothing I have seen out on the web quite explains how one should wire things up on the pic if you're using a transformer-less PSU.
So appnotes are created and design note etc ... but the very simple steps seem to be missing, the questions (FAQ's) and their solutions.
So how do we find news ways of doing things if we are stuck designing only in the confines of a transformer-based supply.
In the early years I remember learning about the effects of capacitive, inductive and resistive circuits.
For example :
In the designs I have seen, people place and swop around the components as the desire almost as though it's a little slap-dash design which may or may not work and your mileage may vary.With a CAPACITIVE circuit, A current will flow through the circuit, first in one direction, then in the other.
No current actually flows through the capacitor. Electrons build up on the one plate and are drained off from the other plate in very rapid succession, giving the impression that the current flows through the insulator separating the plates.
However, a capacitor in an AC circuit does offer resistance to the overall current flow. We define a quantity called the CAPACITIVE REACTANCE, Xc,
For example, I changed my original circuit design around to make it safer (which was a copy and make-up of the Microchip appnotes (or close to it ) , why would they suggest such an unsafe circuit I wonder ?
Then I keep getting told to use the Microchip designs ... yes I would love to but are they the safest ? And most if not all of them are for 120VAC without worked examples for 220V or 230V.
You may have already noted that there COMMON HOT(LIVE) and COMMON NEUTRAL transformer-less supplies.
So after having changed the initial part of the circuit to make it a common neutral supply , this raised more questions
what then? , what else needs to be changed ?
Are the diodes and other components correctly setup and placed the correct way around ?
And as regards the benefits... well
1. it is space saving,
2. is cost (the tiny transformers are extremely expensive here) and
3. is that I can go extremely small if I use SMD components not so ?
I have to put the same circuit in about 15 lights.
If you do manage to see a mistake please let me know.
Anyways that it from me.. I hope that exaplins it so far :-
Kind regards
Dennis
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some more strange circuit designs
Check out this power supply ..take particular note of the input side..
[HTML]http://www.redcircuits.com/Page134.htm[/HTML]
Dave Houston this is the 135KHz injector I was referring to [HTML]http://www.redcircuits.com/Page56.htm[/HTML]
Enjoy
Dennis
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Back in Post #2 of this Thread you were directed to posts which had schematics. The discussion also continued as to what I thought of Microchips App Notes! The product had a production run of several thousand and many hundreds were installed in Hospitals (this I thought was a great idea, since if anything did go wrong, the punter was already in the right place to get assisstance). To my knowledge, in the intervening years, nobody's died and niether has the product, since we never did get any back for service. Looking at the schematic of that product, one end of the TRIAC was tied to NEUTRAL, the other went through the LOAD through a second FUSE (the first Fuse was on the Capacitive Supply to the PIC) to LIVE (you'll note the board had two Fuses). My Gate Resistor from the PIC to the TRIAC was 1K8 - but yours will depend on what your TRIAC's Datasheet tells you.
You go to school and learn the theory of what components can and can't do. You learn the math behind calculating component values. Then, and only then, you will have armed yourself with the knowledge that should stop you from doing something stupid. I've said this before - Darwin had a great theory of "Natural Selection", unfortunately every now and again, good people are also lost along the way.So how do we find news ways of doing things if we are stuck designing only in the confines of a transformer-based supply.
Prime example of lack of knowledge. SMD parts seldom come in high voltage ratings. By reducing the size you reduce the separation between adjacent connections... as a rough guide you need 1mm per 100v. Go pull the Datasheet on an 0805 series Resistor and tell me what the maximum voltage rating is!3. is that I can go extremely small if I use SMD components not so ?
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I was just curious if you could even GET a 0.47uF 500V cap in surface mount, so I did a Digikey search.
The answer is yes, but the only ones I found are ceramic and at $10.45USD each it makes those little transformers start looking pretty cheap.
In through-hole they're available in poly film for about $1 but they ain't particularly small.
I know the answer to Melanies question about 0805 resistor voltage rating. The Vishay parts I use are rated at 150 volts max...
Since you're working on a PIR project, have you seen these?
http://www.zilog.com/docs/devtools/PS0284.pdf
Serial interface to your MCU and can even tell whether something is moving left to right or right to left relative to the sensor. I bought a handful of 'em a couple months ago and am just starting to have fun with them.
I've got parts coming this week to do some serious play with them. Hopefully the UPS man should be bringing me my boards and parts on thursday. Woohoo!
steve
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still researching ...
Hi all
Melanie..
Regarding SMD, I have seen some designs showing SMD components placed after the rectification section section, is it a bad thing to consider SMD in a transformer-less design ?
The voltage ratings are 0805 = 150V and for 1206 = 200V it's quite a whack but not enough for the rectifying stage here.
Would you suggest I utilize that PSU degin you posted mentioned in #2 ?
Just curious as to why the MOV is placed where it is ?
EDIT **** OK I saw it in the forum post ..It's to accomodate for a weakspot at the the zener ****
Did you ever try replacing the 5V regulator with a 5V1 or 5V6 zener instead ?
Have you had any strange anomalies in the PSU's use ?
Have you had any blow?
Is there any ripple or noise encountered on the outputs ? The reason I ask is because I was wondering if it would be ok to add a wireless module to the circuit which the supply would power.
Steve.. the prices certainly are expensive and even for an X2 cap no surface mount !
Those transformers you found certainly are well priced !
Regarding the PIR sensors ...WOW and they do what they do at such a low voltage too ...awesome!
You could easily pack something like that into a matchbox or smaller and have it as a bed-side alarm !
Problem is that it would trigger every time either you or your partner moved in your sleep :-)
Will definitely be looking into those too !
Keep well
Kind regards
Dennis
-
Last edited by Dennis; - 6th January 2010 at 00:04.
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> Would you suggest I utilize that PSU degin you posted mentioned in #2 ?
I make no recommendations... use at your own risk after taking your own requirements and circumstances into account.
> Did you ever try replacing the 5V regulator with a 5V1 or 5V6 zener instead ?
No, because I was using the PICs ADC in my design, and wanted a closer repeatable tolerance and higher current than a Zener could provide.
> Have you had any strange anomalies in the PSU's use ?
None
> Have you had any blow?
No, the design is short-circuit proof and failsafe.
> Is there any ripple or noise encountered on the outputs ?
None beyond the design specification of the 78L05.
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Yes, they're pretty reasonable... and now I notice that they come in an even smaller size!
http://ww2.pulseeng.com/products/dat...2007_02-04.pdf
13 mA @6V, with the same 22mm x 23 mm footprint as the others, but only 12mm high! With a SMD rectifier, regulator, and caps, it's probably not much bigger than a xformerless supply with it's big cap, MOV, and all the
rest.
I'm sure it's still a little more expensive. But maybe not much...
Those are cute, aren't they? And tiny! I'm starting to use them around the house to turn LED "night lights" on and off. When I stumble into the bathroom at night there's enough lumens to find my target without having to fumble for a light switch.Regarding the PIR sensors ...WOW and they do what they do at such a low voltage too ...awesome!
steve
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The efficiency of a Transformer at 50/60Hz is dependent on the amount of iron in it's core... once you drop below about 1.5VA (which is just over an inch cube with an EI30 core) the amount of iron is so small that half the power consumption is used just to heat up the core and windings the efficiency plummets to only 50% or less.
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Melanie, you never cease to amaze me with your practical grasp of such a wide range of issues.
You never know, keep it up and you might just have a future in this "electronics" thing.
Bo
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Well, I'm sure those little transformers aren't the greatest for efficiency, but I don't think the medium small ones (6v@83mA) I've been using are all that bad.
I've got one sitting here on the bench for days with a light (10-15mA?) load on it, and it's only barely warmer than it's surroundings. It can't be dissipating very much energy. Maybe one of these days when I'm feeling less lazy I'll attempt to measure the efficiency on one.
It certainly doesn't heat up like cheap chinese wall wart transformers do.
But how efficient is a xformerless supply if it's not "precisely loaded"? Input current is always the same regardless of load! And unless that fancy X2 cap is sized exactly to the needs of the circuit, it looks like that zener is gonna be dissipating a good dose of heat.
If your load draws a constant current and the cap is sized correctly I can see how it could be very efficient. If the load varies over a wide range as the PIC switches stuff on and off, but the power supply draws the maximum current all the time, then I don't see how that can be very efficient...
steve
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I have measured several X10 modules, when idle, to see how much power they waste. It's not much. http://davehouston.org/x10-power.htm
Some of the highest use transformer supplies. SMPS tend to have the best efficiencies.
Last edited by dhouston; - 6th January 2010 at 18:24.
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Hmmm. 0.4 to 1.4 watts when idle sounds like quite a chunk to me.
Say, I've got a couple of Kill-A-Watt's lounging around here somewhere... I'll take one of these little transformers and put it to the 100 hour test like you did with the X-10 modules.
Edit: I just plugged one in and these little transformers, unloaded, show .02W and .09VA. I'll let it run for a few days and see how the watt-hours add up.
I kind of forget about the Kill-A-Watt's unless the grid power is down and I'm running on backup generator. Then I drag 'em out to keep track of voltage and frequency...
steve
Last edited by Byte_Butcher; - 6th January 2010 at 19:58.
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back to basics and square one ....!
Hi All
This is turning out to be a very interesting discussion..(well at least for me anyway!)
If you look right the way back to the start of this thread I as asking for a little help regarding the calculations mentioned in the Microchip appnote 954.Plenty have been referenced and suggested since then, and thanks to all who have contributed!
To tie things up I wonder if we could start from scratch again and take a close look at (and discuss) the circuit as we build the circuit up in 3 stages.
Hopefully we could get to a circuit which is able to supply a PIC in the correct way and be as safe as an UNSAFE and DANGEROUS circuit could be.
And the stages are :
1. The mains supply stage up to where it becomes DC
2. The circuit-load stage (where we use the 'DC' portion to power the circuit
(a possible zero crossing detector here and LED and pushbutton)
3. The output-load stage (where a load is switched either by means of a relay or a triac.
To start the ball rolling I would like to draw your attention to the attached diagram which depicts the basic types of transformer-less AC to DC power supply.
Each has its own unique chartacteristics (see AC circuit theory study notes or Google them). Understand that there may be phase shifting to consider as well as the zero crossing (these two will not be discussed yet)
SOMETIMES you may need to power a low voltage circuit such as a
microcontroller with HV AC line current.
The basic steps would be to :
1. Use a reactance to limit the current,
2. Rectify the voltage with a diode (half-wave rectification or bridge
rectifier for full-wave rectification),
3. Regulate the voltage with a zener,
4. Add a large electrolytic capacitor to filter out the ripples.
Transformerless supplies don't offer isolation from the HIGH VOLTAGE
line and present a MAJOR SAFETY ISSUE. I will put all of the possible safety tips together in point form and outline the reasons why each one is used or practiced.
I would like to be using a transformer-less CAPACITIVE circuit with common NEUTRAL (although we still have not discussed the effect on the PIC pin and the triac when there is no load!!)
I have not drawn a fuse in the diagrams yet although it is generally agreed that it is a best practice to place the fuse on the LIVE line not NEUTRAL and also not have a second fuse for example one fuse on LIVE and one on NEUTRAL!
With this in mind please could you confirm the following calculations for 220VAC and 50Hz, max current would be +-30mA.
(check the appnote and posts #14 and #16 for the calculations(Thanks Amgen and Melanie))
Calculations as per Microchip Application Note 954 :
(Please note .. Microchip are using a COMMON LIVE example - I am still not 100% sure why)
NOTE - VOLTAGE is either 230V and 240V (RMS) see appnote for 120V
VRMS 230 240
VZ 5 5.1
C1 0.00000047
R1 100
Freq 49.5 50.1
Equation 4
IIN-Min 0.018482937 Amps 18.48 ma
IIN-Max 0.029218819 Amps 29.22 ma
Equation 6
PR1 0.199702245 Watts 0.399404491 Double Watt
Equation 7
PD1 0.217302793 Watts 0.434605585 Double Watt
Equation 8
PD2 0.020453173 Watts 0.040906347 Double Watt
Please feel free to check my values and comment back.
So at this stage all I would like is some consensus on the values calculated and the different types of circuit.
Can we all agree on this so far ?
Kind regards
Dennis
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The 0.4 was the capacitive supply that really was idle; the 1.3 & 1.4 have superregenerative RF receivers which are never truly idle. The point was that capacitive supplies are not inherently wasteful.
Tle last 5 devices all use transformer PSUs as they have serial ports and require isolation.
Last edited by dhouston; - 6th January 2010 at 22:12.
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That's A Sign Post Up Ahead.....
More sites:
Step-down rectifier makes a simple dc power supply
[Electronic Design News]
http://www.edn.com/ednmag/archives/1...98/08df_06.htm
http://www.edn.com/ednmag/archives/1...98/08df_06.pdf
A Capacitor-Fed, Voltage-Step-Down, Single-Phase, Non-Isolated ...
http://www.grix.it/UserFiles/Powermo...L_acfvsdsp.pdf
+++++++++++++++++++ You may skip this part:
In my very best Rod Serling, Twilight Zone, imitation:
“Picture if you will; A man bent over his electronics’ workbench.
A man, with many decades of experience, working for a living, doing precisely what he is doing at this moment.
Analyzing an electronic circuit.
Not just any circuit, but a circuit made by X10.
A consumer circuit, brand new, just out of it’s pristine box, for the first time since it left the factory floor.
The device is powered through a two prong, AC, 120V (USA) power cord.
Only today, instead of analyzing the circuit to repair it, or analyzing it to modify the circuit, he is trying to learn something else.
He is attaching his multi thousand dollar oscilloscope to the X10 device, to find out how it works.
To learn the secrets of it’s communication wave form, if you will. (Rod Serling speak)
To SEE what is going on in this particular mysterious device.
He has done this countless times, to repair, to alter, to learn and to expand, on the knowledge gained by this analysis.
There is no schematic included.
The two wire cord lulls this “searcher of the truth”, into a false impression that the device MUST be isolated, MUST have a small power transformer, somewhere hidden from the casual observer.
Enter - The Twilight Zone:
He FAILS to notice, that there are NO outside connections needed, except the cord.
Just an all plastic case, with all plastic buttons. No jacks, no other cords, just a dead end for the power cord.
Cleverly designed by people who do this for a living.
Just a power cord attached to a plastic case with eight plastic switches.
The output for the device is really, signals going back down the power cord.
Signals riding on the 120V AC power line.
This is know but not thought about by the investigator at this time, overlooked.
He is not aware that this device is powered by a “transformerless” power supply.
With the standard, properly functioning oscilloscope, attached through a 100 times (100x) probe (for conservative safety), the examiner is ready to begin. He has carefully attached the probe, ground on the minus of the filter capacitor, probe on the plus of the low voltage supply.
He has done this, before he energizes the circuit, for obvious reasons.
He now, without the least hesitation, picks up the x10 power plug and plugs it directly into the 120Voutlet.
Also without the least hesitation, he watches half of the printed circuit traces disappear.
A loud bang, a bright flash, a lot of smoke are all that is left of that half of the circuit.
What does he do?
He doesn’t even examine the burnt x10. He knows what happened and why.
He unplugs the warm cord.
He wraps the cord around the unit.
He puts the burnt x10 switch back into its box.
He opens the second identical x10 unit box (an extra, back-up unit).
He opens the unit.
He places the oscilloscope probe on the identical place, only on the new x10 circuit board.
AND
He plugs the new x10 into 120V AC!
DE DE DE DE – DE DE DE DE (that’s Twilight Zone theme music, look it up)
NOT into the same normal AC receptacle, but INTO an isolation transformer. His bench-top isolation transformer.
He would have done this with the first x10 but he wasn’t paying attention.”
That inattentive investigator was... ME. This is a true story.
I had plugged the first (now ruined) x10 into the normal AC receptacle with the neutral side and the line side flipped.
This is why they make and we use line isolation transformers.
++++++++++++++++++++++
You should never service a transformerless supply without one.
-Adam-
Ohm it's not just a good idea... it's the LAW !
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Adam,
I am glad it was not a
Tales from the Crypt
rendition.
Dave
Always wear safety glasses while programming.
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Tales from the Crypt....
Hey Dave,
It might have been, “Tales from the Crypt”, is I was a little bit more careless.
Half of MY circuit traces could have been blown off, if I had touched the circuit board anywhere.
DE DE DE DE... (I gotta stop that theme music)
-Adam-
Ohm it's not just a good idea... it's the LAW !
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De de de de...
Tales from the crypt indeed !
So who ended up shocked and who ended up de-lighted ?
And to create a shift in the TIME-SPACE CONTINUUM .......
You could try wiring LIVE and NEUTRAL across a single pole double throw switch making sure you have the correct current rating , place the project box on the floor making sure your friend is leaning over the box monitoring the power LED (Make sure the top lid of the box is removeable - all securing screws removed) THEN plug your procjet in with the wall switch in the OFF position and THEN ....using a broomstick and jokingly tell your friend it's for safety sake and THEN...from a distance flip the switch to the ON position.
RESULT :
1 X very surprised friend
1 X totally blackened pc board
1 X extremely well toasted and burned out SPDT switch (all ratings ignored) :-)
ISOLATION ISOLATION ISOLATION !
Now try to maintain proper stabilization of this channel without creating a situation of over-modulation
Steve, Adam .. are you guys kinda volunteering yourselves to be PSU testers for this one ??
Could we get captures for each stage of testing ? one cam on you and one on the circuit ?
....and the scene begins with a skull and cross-bones with a caption saying something like DON'T DO THIS AT HOME ?
Kind regards
Dennis
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Simpler and safer is to use a stepdown transformer connected to the powerline and view the communication wave form through it. You don't even have to open the X-10 modules. A high pass filter passes 120kHz and blocks the 60Hz.
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yes!
Yes agreed or use a lower AC voltage at the same frequency running completely off the mains ?
Dennis
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Me? Sure, I'll test it. I'm not afraid. I've got an isolation transformer and know how to use it.
I suppose one of my more memorable "120V bench accidents" was repairing an old radio that had the neutral connected to its metal chassis. And an old worn 2 wire cord that could plug in backwards in certain outlets.
I managed to plug it in so that the neutral chassis was actually a hot (120VAC) chassis. When I went to clip my scope probe ground onto the chassis, there was a brilliant flash and bang. I was dazed but unharmed, and the scope probe was destroyed.
Live(d) and learn(ed)...
steve
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beyond the far reaches of the galaxy ....
Steve :-) ....
OK .. I actually un-voluntarily spat the sip of coffee out trying to suppress the laughter :-) and am still having a good chuckle ... laughing with you not at you!
I had a similar incident on an old Zenith CGA and EGA monitors whose chasis' was live/hot.
In order to get the colours and sync right one had to use a very long trim-pot tool , sometimes we had to improvise and use a long screw-driver because all of the trim-pot tools were out of the workshop in the field with other technicians to make matter worse we would place the monitor on a metal trolley with wheels.
With the right (wrong!) combination of screw-driver and hand grips and a kinda left-hand suzuki method I very quickly was sent hurtling with an ear-piercing yell across the workshop into the bench behind me knocking my mentor straight off his feet !
Well needless to say after the initial shock was over and it was established that I was OK, the entire workshop spent the rest of the day laughing to crack their sides. And I definitely feel quite wound up after that.
There's that statement in the Star Trek intro "to boldy go where no man (or woman) has gone before"
There are some options of course
"to boldly go where no man (or woman) has come back from before"
or
"to boldly go where men (and women) have come back from before"
or
"to boldly go"
finally ..."just don't go !"
Thanks for the offer .. would you like to try the circuits a few posts ago or would you like something more finished ?
Awaiting an episode of the unexplained now I think !
By the way this was an interesting find of yours..! Definitely puts and angle on things !
I was wondering all through the article where the bleed resistors where ... and then saw them and mention of them in the last few pages !
Kind regardsA Capacitor-Fed, Voltage-Step-Down, Single-Phase, Non-Isolated ...
http://www.grix.it/UserFiles/Powermo...L_acfvsdsp.pdf
Dennis
Last edited by Dennis; - 7th January 2010 at 22:43.
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an UPDATE ***
Gee suddenly this thread has quietened down :-(
There were no explosions, no loud bangs , nothing that went bump in the night...
No loud bangs, nothing burned out ...!
I decided to go ahead and build the circuit for testing ... nothing worked initially :-( the LED which I had enabled to go high every 15 seconds didn't even come on :-(
I went over it again with a fine-toothed comb..and found my 100uF and 100nF cap were in the wrong places.
I had programmed my PIC outside the board of course (no ICSP implemented yet !!) the program simply blinks an LED(GPIO.5) this would tell me the PIC has voltage and there would be no need for voltage measurements and also sets the TRIAC gate (GPIO.0) to go high for 15 seconds and the low for 15 seconds.The TRIAC in turn turns on the light buld for the same amount of time.
After correcting the capacitor issue,I put my welding glasses on and a pair of earmuffs and I used a broom stick to flip the AC wall switch :-)
Well the LED came on ..YAY :-) but the connected light bulb sadly did not !
SIGH !
The I looked back at the the circuit schematic and the calculations and it dawned on me that the TRIAC gate current may not be enough.Initially I had just popped in a 1K 1/4 Watt resistor just as a placeholder in my schematic with the idea that it may or may not work.
I quickly flipped the wall switch off, unplugged the extension cord (yes that too !) and unplugged the circuit board (strip-board for now), I made sure not to touch the large caps while unsoldering the gate resistor (R3) and replaced it with a 390R one!
Again repeating the same steps, earmuffs etc,I once again powered on the circuit .....
And to my absolute surprise the light bulb came on then 15 seconds later it switched off and the LED came on ! So when the LED is ON the LIGHT is OFF and vice-versa !
WHY ?
How could both be set to come on at the same time ?
But YAY it works :-)
There is a slight flicker when the light buld is on and I'm thinking it may be the TRIAC resistor or ??? the mind wonders...!
So now I need to test more.
The questions now are :
1.Is it the TRIAC gate resistor causing the flicker ?
2. Are there any suggestions for the the value for R3 ? (Check earlier posts for BT-139 gate current values and specs.
3.Cap C1 value is 275V and I'm thinking rather to use a 400V rated X2 instead, any thoughts on this ?
4. What's a concern is in times of NO LOAD , what will life be like for the PIC control PIN and the TRIAC gate ?
5.Other options include using an opto-isolator (possibly a MOC3023 or 30XX) in conjunction with or stand-alone ..any thoughts ?
On a final note... Please note that the attached circuit design is merely for testing and discussion purposes and has NOT been completed nor cleared for safe use of any kind and is missing several safety elements like a FUSE, MOV and a parallel bleeder resistor across C1.
Also note that this is a HIGH VOLTAGE circuit and neither I nor anyone else posting on this thread assumes any liability which may arise from any aspect of the circuit and or its development and/or use.
Working with circuits like this one are HAZARDOUS and UNSAFE and could result in serious injury and/or death !
DO NOT build this circuit unless you have HIGH voltage experience, rather use a transformer based circuit which is isolated from the LIVE AC supply.
You have been warned!
Steve ... are you ready to measure ? ;-)
Any thoughts would be appreciated
Oh .. and last but not least a popquiz question... Am I using a COMMON LIVE design or a COMMON NEUTRAL design ...and why ?
Kind regards
Dennis
Last edited by Dennis; - 11th January 2010 at 23:09.
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Gee, that's kind of anticlimactic after all the DANGER warnings, now isn't it?
No conflagrations = Congratulations.
Maybe. Honestly, I think I'd use an opto-isolator to drive the triac. But that's just the way I am...The questions now are :
1.Is it the TRIAC gate resistor causing the flicker ?
Refer to answer #1...2. Are there any suggestions for the the value for R3 ? (Check earlier posts for BT-139 gate current values and specs.
If your mains is 220V, then I 'd use a 400V rated cap. No way, on the 275V.3.Cap C1 value is 275V and I'm thinking rather to use a 400V rated X2 instead, any thoughts on this ?
Not quite sure of the question here, but I think it goes back to answer #14. What's a concern is in times of NO LOAD , what will life be like for the PIC control PIN and the TRIAC gate ?
Hmmm. Yeah, I think an opto-isolator would be good.5.Other options include using an opto-isolator (possibly a MOC3023 or 30XX) in conjunction with or stand-alone ..any thoughts ?
Rat's, and I just sent my nomex suit to the cleaners and loaned my 10' insulated pole to my neighbor.Steve ... are you ready to measure ? ;-)
Say, don't you think it might be a good idea to put a small 5 volt zener from pin 5 to ground? I know that 1M is a pretty high value resistor and the PIC pins have some protection against over-voltage, but there's something kind of creepy about just connecting a PIC port pin to that high of a voltage, even through a big resistor. Probably no big deal, but it makes me nervous connecting that pin to 220v with just a resistor.
steve
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a reply :-)
Hi all
OK 8 hours of flashing a 60W light bulb and no issues yet , Im feeling a little 'strobed-out' though :-), battling to decide to watch the light or the LED :-)
I'm also more keen on the OPTO , just wondering how it will survive the capacitive 5V floating circuit on the PIC side of things ... will explain more a little later.
Regarding the PIC for zero-crossing sensor , have you read the Microchip appnote 236a ? It should make you feel a little more confident , but I can try a diode if you like ?
Now about those screen caps and measurements :-) haul out that isolation transformer and scope and let's get some more info :-)
If you are curious and have the time of course ..
Kind regards
Dennis
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Nope, haven't read it. But I will in the morning.
But if it's OK with the folks at Microchip, then I guess it's OK with me.
I will read the appnote tomorrow... zero crossing detector is one of those things that will come in handy for me someday.
steve
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Fantastic
Hi all
Steve ...
Also check out the posts by Dave Houston regarding the x10 info ... they have indeed been using an MCU's for many years and I recall seeing a post or two by Dave referencing certain models in particular even a PIC 12XXXX if I'm not mistaken.
You could also always conduct AC testing on low-voltage 'downlights' (not sure what you call them in the US or Europe ... ?
Keep those posts coming , this is a very interesting thread so far :-)
Oh and see post 66 (clickety clicks :-) )
Kind regardsOh .. and last but not least a popquiz question... Am I using a COMMON LIVE design or a COMMON NEUTRAL design ...and why ?
Dennis
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Common Live so that the triac is switching the live supply to the load.
If the circuitry was common neutral then the triac would also be switching neutral with the result that the entire load would be live when the circuit appeared to be OFF.
Keith
www.diyha.co.uk
www.kat5.tv
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This “excellent adventure”
Hi Dennis,
Great work so far. Let us know how things are going.
Especially how the ICSP works out, on the non-isolated circuit board.
This has turned into an interesting thread. A mix of past and future adventures in electricity land.
I really like the guys telling (on themselves) about the mishaps that have befallen the adventurous types. That is how we learn. Sometimes just being told carries little weight.
Good question!
I would guess the answer is: It is either a “COMMON LIVE” design OR a “COMMON NEUTRAL” design depending upon whichever way you happen to insert the plug. Why? Because “Sometimes just being told carries little weight.”
Keep us up to speed on this “excellent adventure”. Your posts are a great mix of adventure, work, learning, teaching, doing, telling, asking and just plain fun. –Adam-
Ohm it's not just a good idea... it's the LAW !
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perhaps a mystery begins to unravel itself .. ? or begins ..?
Hi guys
With reference to post #66 and the rest that follow and everything else prior to it.
Interesting indeed !
Keith ..AWESOME reply!
I agree with you here
Ok now for the beginning of the mystery and to add to this threads confusion you added this in :-)triac is switching the live supply to the load.
So from that statement we should assume COMMON LIVE is the supply of choice (in terms of being a little safer) not COMMON NEUTRAL ? Assuming of course that this circuit is indeed a COMMON LIVE circuit ?If the circuitry was common neutral then the triac would also be switching neutral with the result that the entire load would be live when the circuit appeared to be OFF.
Any comments on the above statements ?
Steve ....
Nice...! You threw in another side-winder, in fact, you mentioned something very real !
A two prong(pin) plug in most countries (correct me if I'm wrong ?) is easily reversed , in other words pluged in the other way around .. both sides same sides kind of thing so if I decide to design my PSU with the left prong as LIVE and the right prong as NEUTRAL .. all fine and dandy but then I unplug the device, put the pulg into the wall socket the other way around and suddenly everything is changed around :-)
Does this mean I should re-design my whole circuit ?
UH OH !
Well I encountered this dilemma a few nights back ... just before I got the broomstick, earmuffs and rubber gloves out and got all kitted up, I thought "Gee on this two-prong plug what happens when everything turns around ?"
"Will the circuit blow? What will the effect be? Will I need to change everything?"
So it works , turned either way around ! ( AC @ 50 Hz hmmm? )
And ..on the safety side is this circuit any less dangerous than a lamp that takes a bayonet or screw in light bulb ? Let's face it there is 110/120VAC or 220/230/240VAC right at the contacts where you screw the light in , not so ?
What about the computer AT form not so long ago which had mains voltage right at the front panel pretty much like may household appliances,TV's and radios before soft-power switches became the flavour of the day.
OK my next mission would be to alter the circuit so that the 'circuit ground' is the LIVE line in the schematic but .. do I really need to ?
Awaiting more comments and thoughts :-)
Oh and the question still remains ... is the circuit in post # common live or common neutral ? and why ?
Kind regards
Dennis
Last edited by Dennis; - 13th January 2010 at 21:42.
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Living in a country where every mains outlet is a 3 pin socket so polarity reversal is impossible unless the actual outlet is incorrectly wired I would say that common live *should* be the supply of choice particularly if the load it was controlling was external to this box of tricks so that it would be recieving a correctly switched supply.
Irrespective of supply polarity, becuase this circuit is tied directly to one leg of the mains supply it should be totally enclosed and should never be worked on except via an isolation transformer.
All "basic" light dimmers have a common live supply as they are only connected to the live and load.
Keith
www.diyha.co.uk
www.kat5.tv
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Hi again
Nice one keith ...safety and isolation for sure! Have you read the earlier posts ?
And those plugs quite often contain fuses (probably on the LIVE) not so ?Living in a country where every mains outlet is a 3 pin socket so polarity reversal is impossible unless the actual outlet is incorrectly wired I would say that common live *should* be the supply of choice particularly if the load it was controlling was external to this box of tricks so that it would be recieving a correctly switched supply.
And the looking at the APPNOTE that I referred to in post #1 under the designing for safety heading you would see the fuse placed on one of the lines as well as a fuse and a bleeder/'safety' resistor sitting parallel with C1.
Now let's chat about the 2 prong device that need to be plugged in the countries you're referring to.
We need some sort of adapter to plug the 2 prong device into the 3 prong plug right ? Does th adapter contain a fuse as per country electrical regulations (if any ) ?
So again plugging a PSu like this one into the adapter, one can plug in either way ... and yet again NEUTRAL and LIVE are switched around (in the circuit of course)!
If this indeed is the case then we are right back at the million dollar question
"Is this circuit Common LIVE or COMMON NEUTRAL ? And why ?"
And then we must look at the designing for safety aspects where we discussed fuses.
One of the original draughts had two fuses , one on each line, and a point or two were raised about one of the fuses (the one on the neutral line) would be pointless. Yes indeed it probably would be useless as well as unsafe ...IF this circuit contained an earth(real ground) !
But alas, the circuit has no earth point or connection at all !
SO it seems this circuit will always 'FLOAT' either at 5volts(or whatever you designed it for) below live or 5Volts above neutral.
In earlier posts I showed circuit diagrams of common live and common neutral from various references.Circuits with components changed around, in different places forcing flow in different directions.
Are these circuits incorrect ?
Sadly I don't have an oscilloscope or an isolation transformer at my disposal anymore but I certainly will check/test/build blow-up each circuit depicted and feedback so we can continue this discussion.
Anyone feel like building a calculator to calcualate the APPNOTE referred to in post #1 and/or the circuit in #66 ?
Regarding the 'BOX OF TRICKS' you mention ...
If all of you that are following this post have some time , go and google for 'Ben Franklin flyng a kite in the rain with a key tied to the string' to attract lightening strikes.
And then along the lines of safety and climate change try google H.A.A.R.P.
Sure... why not try heat the ionosphere at it's thinnest points at the poles to blow a hole in it just to see what happens .. now that's safety for all mankind not so ?
All thanks to folks like Tesla, Franklin and ...aaargh let's not go there!
And is the H.A.A.R.P experiment over ... well apparently (will we ever really know?), but google earth and satellite pics show the facility plain as day !
Oh well at least we can get answers about the PSU circuit :-)
Kind regards
Dennis
Last edited by Dennis; - 14th January 2010 at 00:17.
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It's suddenly gotten really quite in this thread :-(
Hi guys ...
Why so quiet ?
Just a quick post to let you all know I'm still around ... no explosions, shocks or fire yet !
The test PSU is still working...
I got busy with real work suddenly and haven't had a chance to experiment more :-(
Will definitely update on the weekend !
Kind regards
Dennis
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Couldn't resist
In case some of you didn't see this in another thread.....
www.picbasic.co.uk/forum/showthread.php?t=2736
any news on the code from Kamikaze47, seems to have disappeared.
You are right. Last seen, June 2006.
You expect to see people disappear from threads labeled:
Interfacing AC power lines....
...transformerless DC supply...
How to design without opto-couplers ...
How to measure high voltage while standing in a bucket of water...
But not from a thread labeled, “AT/PS2 Keyboard - PIC Interface?” ?
Then again we have to consider his user name!
Kamikaze47 where are you??
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Dave
Always wear safety glasses while programming.
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Quote from the past...
Bo quoted from the past: 30th March 2007, 14:10, not currently.
Kamikaze47 has been back many times since the original posting.
See also Melanie’s hilarious post (standing in a bucket of water) #33 two below this quote!
http://www.picbasic.co.uk/forum/show...0&postcount=33
-Adam-
Ohm it's not just a good idea... it's the LAW !
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The silence has been deafening!
Deafening silence defined is :
'A silence or lack of response that reveals something significant, such as disapproval or a lack of enthusiasm'
Bo ....
Definitely some valid chirps :-) apparently apparitions do re-appear and it's not all smoke and mirrors :-).You expect to see people disappear from threads labeled:
Interfacing AC power lines....
...transformerless DC supply...
How to design without opto-couplers ...
How to measure high voltage while standing in a bucket of water...
But not from a thread labeled, “AT/PS2 Keyboard - PIC Interface?” ?
Then again we have to consider his user name!
Kamikaze47 where are you??
Now I'm wondering if you have are planning to interface and AT/PS/2 keyboard to the AC mains line that delivers a different 'ZAP' at each keypress ?? Could it be solar-powered or we gonna just stick to the original hookup to directly the substation on 3-phase ?
The silence in this thread has me a little worried too since i haven't seen Steve around since I asked about some possible measurements (In the post before he said he wasn't to do a few measurements 'cos of his trusty isolation transformer ), I haven't seen any activity on this thread from him since then.
And all of a sudden this thread went extremely quiet...!
Shocking I tell you !
Kind regards
Dennis
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