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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Tue 03, 2012 5:07 pm 
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Location: Baltimore, MD
Indiana Radios wrote:
Seeing how incandescent light bulbs are slowly being phased out .


I really don't think the incandescent is going anywhere. The 100W bulbs that were supposedly "phased out" last year are still in good supply around here and are being replenished. The 60W and 40W definitely aren't going away anytime soon. We use the standard GE incandescents and usually get at least a year out of them at least, sometimes more.

As long as people like me refuse to buy the CFLs, they will make incandescents. Believe me, there is still a big market for them.

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Tue 03, 2012 5:14 pm 
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I too am wondering about the deal with incandescents. I could be wrong, but I'd understood that all of the specialized bulbs would still be made: aka- candelabra, big globes, oven lights, and so on. What I've noticed around here are bulbs with odd wattages: 60 watts are now 57 and 75 are now 68 or something.


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Tue 03, 2012 6:08 pm 
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Location: Santa Rosa, CA
Quote:
An alternative would be to install light dimmers. They also sell dimmer sockets for table lamps. It would do the same thing,


There is a down-side to using dimmers, especially if you like to listen to AM radio. Dimmers chop the AC sine wave during mid-cycle causing all sorts of RFI. The diode button switches off for a half cycle and the switching occurs at a "zero point" of the waveform. You can filter dimmers, but the solution usually isn't perfect.

Rich


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Fri 13, 2012 5:56 am 
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better than a TRIAC dimmer (which I've done a loooot of research on - they are noisy little bustards) would be a VariAC which is basically a variable-tap transformer (isolating or non-isolating are available) but they COST something ferocious.

the problem with a TRIAC is that it is turning on partway through the waveform. the sudden spike needs to be rapid enough that it doesn't leave the TRIAC semiconductor in a partially-conductive state (which causes heating), while on the flip side, a sharp rise causes hellish noise on the line.


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Fri 13, 2012 6:37 am 
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Location: Powell River BC Canada
Triacs had a companion part called a Diac, in series with the gate. This snapped it on
fairly quickly.

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Fri 13, 2012 10:50 am 
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bobwilson1977 wrote:
I too am wondering about the deal with incandescents. I could be wrong, but I'd understood that all of the specialized bulbs would still be made: aka- candelabra, big globes, oven lights, and so on. What I've noticed around here are bulbs with odd wattages: 60 watts are now 57 and 75 are now 68 or something.


From what I understand, they are still going to eventually phase out regular incandescents. I think the phase out was delayed.

The weird wattages you see are the new bulbs that are still incandescent but save energy. I've seen some 95 watt incandescents that are supposed to be longer life than standard 100s. There are also the new halogen bulbs that are supposed to save energy. They seem to put out the same amount of light as a standard 100 watt incandescent, and they only use 72 watts. The one I have in my kitchen gets frequent, daily use and still is going six months later. Isn't that expensive, either.


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sat 14, 2012 1:14 am 
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radiotechnician wrote:
Triacs had a companion part called a Diac, in series with the gate. This snapped it on
fairly quickly.


the DIAC is just a "consistency" part

when a TRIAC is built, it isn't actually tuned at high precision to react in the exact same voltage going each direction - a DIAC is, however. so you'd use a ~36v (might be +31v, -38v) TRIAC paired with a tuned 42v DIAC to make a 42v TRIAC circuit. more expensive TRIACs will have a built-in DIAC in the same TO-220 case; make sure you know whether the part you're using has an integrated DIAC when building a circuit

... or you could find an optoisolated TRIAC and avoid the gating voltage issue entirely (they can be operated at Logic voltages, ie, 3-5vDC)


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sat 14, 2012 4:01 am 
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Hyratel wrote:
better than a TRIAC dimmer (which I've done a loooot of research on - they are noisy little bustards) would be a VariAC which is basically a variable-tap transformer (isolating or non-isolating are available) but they COST something ferocious.

the problem with a TRIAC is that it is turning on partway through the waveform. the sudden spike needs to be rapid enough that it doesn't leave the TRIAC semiconductor in a partially-conductive state (which causes heating), while on the flip side, a sharp rise causes hellish noise on the line.


Variacs are cheap if you buy from folks like we have here, and on other hobby forums. :) $30-$50 seems average for a small one that handles a few hundred watts. Of course, a new one will HURT your wallet. There aren't too many ways that manufacturers can "cheat" with them - a donut of iron and copper... is a donut of iron and copper. :lol:

Yes, your standard cheap(or not) light dimmer is TRIAC-based and very noisy(often even audible). Fan dimmers are better, but cost about 2x as much. They are TRIAC driven as well, but they have caps and nice big inductors to smooth out the waveform - some motors can't tolerate what light dimmers put out and they are dangerously exposed to voltage spikes and half-wave "leaks". Lightbulbs couldn't care less, but motors will definitely mind.

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sat 14, 2012 4:39 am 
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Joined: Sep Fri 02, 2011 1:55 am
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ideally, you'd want something like an Isolating PWVARIAC (I'm making sh* up as I go, based on my own knowledge and experience), that is to say, a 1:1 isolating transformer that runs a PWM of a high multiple of 60Hz timing, splitting the power across two discrete MOSFETs or high-test BJTs, which would operate in result like a variac...
damn, now I want to make one!

PS - if I'm blowing smoke out my arse, someone knock me out with a phonebook


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 2:51 am 
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Joined: May Tue 30, 2006 4:46 pm
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Location: Santa Rosa, CA
Quote:
the DIAC is just a "consistency" part

when a TRIAC is built, it isn't actually tuned at high precision to react in the exact same voltage going each direction - a DIAC is, however.


TRIACs aren't built with much precision at all. They are turned ON by a gate current, not a voltage. There is considerable variation from lot to lot on trigger current. The manufacturer only guarantees that all of the TRIACs will turn on with specified min. gate current. That's also subject to temperature variation. A DIAC turns on when a specified voltage is reached, so it acts as a gate trigger for the TRIAC.

Anything you do with hi freq. PWM is going to have a potential noise problem (RFI) due to the sharp rise and fall times.

Yes, VARIACs are nice, but try putting one in a single gang AC wall box! They used to be used for theater stage lighting, but I think TRIACs and SCRs are now used pretty much everywhere.

Rich


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 3:32 am 
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Rich, W3HWJ wrote:
TRIACs aren't built with much precision at all....

Anything you do with hi freq. PWM is going to have a potential noise problem (RFI) due to the sharp rise and fall times.

... TRIACs and SCRs are now used pretty much everywhere.


Yep, TRIACs were developed to control AC power efficiently, which means PWM. Any precision was in the timing, not the trigger value. DIACs are just convenience, that are at a lower voltage than a neon bulb. But they're not always used with TRIACs. Of course, PWM, means that the TRIAC can switch ON anywhere in the AC sinewave cycle, creating a complex waveform.

A perfect sinewave, will only have one component in the frequency domain. Anything other than that will have other frequency components. Usually harmonic multiples of the primary frequency. The sharper the rise (or fall), the higher the frequencies. Well into the RF range. That's just the simple math behind PWM.

Every dimmer, I know, has a TRIAC (or some other PWM methodology) in it, with its associated noise.

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 11:43 am 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
Triacs can be made to turn on in any of the four quadrants, but cant turn off until the
next zero crossing, and in cheap fan and light controllers, the triac-diac pair offers the
least part count for 60 Hz use in Q1 and Q3. You cant blow it out like a SCR
just by reversing the current flow, i.e. with a capacitor , because it just turns on
in Q3. Bummer if you want a simple ring chaser.

They also were used for slow speed AC outputs on PLCs and could directly
operate 120 volt motor starters but were not trusted to drop out where life
or limb was involved. When TDC automation came along we got good
at intuiting just which triac module had gone goofy and was wont to
switch on or not when it felt like it.

Have they evolved any, substantially in the past 40 years?

Or are they just a burned out patent dead-head manufacturers are
obliged to furnish because there is nothing better?

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 7:09 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10035
Location: Santa Rosa, CA
We are getting a bit off topic here, but I think the discussion of TRIACs is useful.

Quote:
Yep, TRIACs were developed to control AC power efficiently, which means PWM.


TRIACs are NOT used in PWM (pulse width modulation). PWM means you can turn a pulse ON and OFF. A TRIAC can only be gated ON. It requires the line current to go through zero to commutate OFF. TRIACs and SCRs (thyristors) use Phase Control to control line current. By delaying the turn on of the device until later in the AC cycle, you can choose how much of the AC waveform you want to conduct, hence controlling the power to a load.

Quote:
Triacs can be made to turn on in any of the four quadrants, but cant turn off until the
next zero crossing, and in cheap fan and light controllers


TRIACs are conventionally used as AC controls in Q1 and Q3.

Rich


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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 8:03 pm 
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Quote:
Triacs can be made to turn on in any of the four quadrants, but cant turn off until the
next zero crossing, and in cheap fan and light controllers


That's because, while current is flowing, the device is latched ON. With the gate stimulation removed, the current will go to zero, at the zero crossing, and device will then turn off.

SCR's (basically half a TRIAC, sort of) use to be used in DC powered circuits, for that latching ability. To turn it off, the current in the main path had to be removed. This was either done, because the source was a transient source like a charged cap. The current path was opened, or an additional path created, to divert the current. Current diversion was often done if the SCR was in a ring counter circuit. SCR and TRIAC circuits have been restricted to power applications, after ICs came into common use.

Rich, W3HWJ wrote:
TRIACs are conventionally used as AC controls in Q1 and Q3.


Very true, in common dimmers, or circuits using opto-isolated TRIACs (AC solid state relays). Logic TRIACs, which are electrically connected to controlling source, use Q1 & Q4. Difference in a logic TRIAC , is that its gate is a tad more sensitive than other TRIACs.

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 Post subject: Re: Help, No More "The Button" Incandescent Light Bulb Saver
PostPosted: Jul Sun 15, 2012 8:27 pm 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
Why they work so well, as far as long life is concerned, in dimmers and fantrolls is that
the are self -snubbers, unlike SCRs. A transient just turns them back on and the lightbulb
takes the brunt of the energy.

Is is good processors took over. SBS, SUS, and those of that ilk.

Here's a bit af GE humor found in an app note years ago:
Attachment:
GE Humor.jpg
GE Humor.jpg [ 181.87 KiB | Viewed 948 times ]

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VE7ASO VE7ZSO
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