On Saturday, September 26, 2020 at 2:33:16 PM UTC-4, Tabby wrote:> On Saturday, 26 September 2020 17:37:43 UTC+1, jla...@highlandsniptechnology.com wrote: > > On Sat, 26 Sep 2020 17:11:54 +0100, Piglet <erichpwagner@hotmail.com> > > wrote: > > >On 26/09/2020 15:56, jlarkin@highlandsniptechnology.com wrote: > > >> On Sat, 26 Sep 2020 08:54:01 +0100, Piglet <erichpwagner@hotmail.com> > > >> wrote: > > >>> On 25/09/2020 18:36, John Larkin wrote: > > > >>>> Given that this is an electronic design forum, we should design > > >>>> something. I could start. Maybe some others can suggest circuits. > > >>>> > > >>> > > >>> I already started - didn't you see my design? > > >>> > > >>> piglet > > >> > > >> Sorry, missed that one. I'd delete the EMI filter, except with a > > >> standard dimmer as the starting point, it's free already. > > >> > > >> What about ramping down the value of Rt over time? Some variation on > > >> one of my circuits? NTC thermistor? > > >> > > >> Maybe the entire circuit could be one NTC thermistor, one of those > > >> inrush limiter things. > > >> > > >> > > >> > > > > > >Yes, I think Tabby (or someone) suggested an NTC already. > > > > > >piglet > > > > Maybe heat sink it to a chunk of aluminum or two to slow down the > > turn-on? > > With 20w of load a biggish one or 2 may be slow enough as is. Heatsinking it would require great thermal contact to be effective in slowing interior heat-up, most THs aren't a good shape for that. Laser slice them? :) > > You might be able to slow it further with a series cap. It takes the LED closer to the point where it dims, ie lower mains v, and Xc + Rth is going to be larger at any time during warm up. And if you really must you could slow it yet again with a PTC Thermistor across the bulb. > > There are so many ways it can be done. And Ricky is getting snipey again.Yes, I suggest a method of solving the problem that doesn't need to be spiced, is guaranteed to work out of the box and is very affordable... that's snipey. Larkin doesn't take the time to simulate the circuits to show they really work and I'm not going to take the time to find the guy an exact part number. This is not a project I would want to spend significant time on designing a circuit that can have hidden risk of fire and/or shock when there are off the shelf solutions. If you don't mind that sort of risk, there are off the shelf solutions on aliexpress for a song, probably cheaper than the parts to build a dimmer and won't limit the circuit to only dimming and at just one rate. This conversation has dragged out for days already. I expect it will be some time longer before anyone has a circuit that might actually work. It's not the sort of thing I would be wanting to design a circuit for. I would want to get it done and move on to more useful endeavors. That's why I recommended a module. -- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
Slow fade-in circuit
Started by ●September 23, 2020
Reply by ●September 26, 20202020-09-26
Reply by ●September 26, 20202020-09-26
On 9/26/2020 2:33 PM, Tabby wrote:> On Saturday, 26 September 2020 17:37:43 UTC+1, jla...@highlandsniptechnology.com wrote: >> On Sat, 26 Sep 2020 17:11:54 +0100, Piglet <erichpwagner@hotmail.com> >> wrote: >>> On 26/09/2020 15:56, jlarkin@highlandsniptechnology.com wrote: >>>> On Sat, 26 Sep 2020 08:54:01 +0100, Piglet <erichpwagner@hotmail.com> >>>> wrote: >>>>> On 25/09/2020 18:36, John Larkin wrote: > >>>>>> Given that this is an electronic design forum, we should design >>>>>> something. I could start. Maybe some others can suggest circuits. >>>>>> >>>>> >>>>> I already started - didn't you see my design? >>>>> >>>>> piglet >>>> >>>> Sorry, missed that one. I'd delete the EMI filter, except with a >>>> standard dimmer as the starting point, it's free already. >>>> >>>> What about ramping down the value of Rt over time? Some variation on >>>> one of my circuits? NTC thermistor? >>>> >>>> Maybe the entire circuit could be one NTC thermistor, one of those >>>> inrush limiter things. >>>> >>>> >>>> >>> >>> Yes, I think Tabby (or someone) suggested an NTC already. >>> >>> piglet >> >> Maybe heat sink it to a chunk of aluminum or two to slow down the >> turn-on? > > With 20w of load a biggish one or 2 may be slow enough as is. Heatsinking it would require great thermal contact to be effective in slowing interior heat-up, most THs aren't a good shape for that. Laser slice them? :) > > You might be able to slow it further with a series cap. It takes the LED closer to the point where it dims, ie lower mains v, and Xc + Rth is going to be larger at any time during warm up. And if you really must you could slow it yet again with a PTC Thermistor across the bulb. > > There are so many ways it can be done. And Ricky is getting snipey again. > > > NT >I think a thermistor might work with some cheapo LED bulbs but the good-quality ones have an integrated buck converter that likely has some undervoltage lock-out on the rectified mains input. I think those type which are "dimmable" accomplish it through an auxiliary circuit to sense if the input is chopped and hold-off the lockout if so and translate the angle of the zero-crossing to an appropriate set-point for the regulator.
Reply by ●September 26, 20202020-09-26
On 9/26/2020 8:53 PM, Ricketty C wrote:> On Saturday, September 26, 2020 at 2:33:16 PM UTC-4, Tabby wrote: >> On Saturday, 26 September 2020 17:37:43 UTC+1, jla...@highlandsniptechnology.com wrote: >>> On Sat, 26 Sep 2020 17:11:54 +0100, Piglet <erichpwagner@hotmail.com> >>> wrote: >>>> On 26/09/2020 15:56, jlarkin@highlandsniptechnology.com wrote: >>>>> On Sat, 26 Sep 2020 08:54:01 +0100, Piglet <erichpwagner@hotmail.com> >>>>> wrote: >>>>>> On 25/09/2020 18:36, John Larkin wrote: >> >>>>>>> Given that this is an electronic design forum, we should design >>>>>>> something. I could start. Maybe some others can suggest circuits. >>>>>>> >>>>>> >>>>>> I already started - didn't you see my design? >>>>>> >>>>>> piglet >>>>> >>>>> Sorry, missed that one. I'd delete the EMI filter, except with a >>>>> standard dimmer as the starting point, it's free already. >>>>> >>>>> What about ramping down the value of Rt over time? Some variation on >>>>> one of my circuits? NTC thermistor? >>>>> >>>>> Maybe the entire circuit could be one NTC thermistor, one of those >>>>> inrush limiter things. >>>>> >>>>> >>>>> >>>> >>>> Yes, I think Tabby (or someone) suggested an NTC already. >>>> >>>> piglet >>> >>> Maybe heat sink it to a chunk of aluminum or two to slow down the >>> turn-on? >> >> With 20w of load a biggish one or 2 may be slow enough as is. Heatsinking it would require great thermal contact to be effective in slowing interior heat-up, most THs aren't a good shape for that. Laser slice them? :) >> >> You might be able to slow it further with a series cap. It takes the LED closer to the point where it dims, ie lower mains v, and Xc + Rth is going to be larger at any time during warm up. And if you really must you could slow it yet again with a PTC Thermistor across the bulb. >> >> There are so many ways it can be done. And Ricky is getting snipey again. > > Yes, I suggest a method of solving the problem that doesn't need to be spiced, is guaranteed to work out of the box and is very affordable... that's snipey. > > Larkin doesn't take the time to simulate the circuits to show they really work and I'm not going to take the time to find the guy an exact part number. > > This is not a project I would want to spend significant time on designing a circuit that can have hidden risk of fire and/or shock when there are off the shelf solutions. > > If you don't mind that sort of risk, there are off the shelf solutions on aliexpress for a song, probably cheaper than the parts to build a dimmer and won't limit the circuit to only dimming and at just one rate. > > This conversation has dragged out for days already. I expect it will be some time longer before anyone has a circuit that might actually work. It's not the sort of thing I would be wanting to design a circuit for. I would want to get it done and move on to more useful endeavors. That's why I recommended a module. >Clearly the answer is to build an artificially-intelligent dimmable LED bulb that can automatically adapt itself to a wide range of standard dimmer circuits. I'm only half-kidding
Reply by ●September 27, 20202020-09-27
On a sunny day (Sat, 26 Sep 2020 14:42:14 -0700) it happened jlarkin@highlandsniptechnology.com wrote in <badvmftp4m6r9vfsbvt0a7u9a28og9sm9j@4ax.com>:>The data sheet prohibits me from copying or printing it. OK, deal.Here is my take, untested: http://panteltje.com/pub/triac_trigger_r_IXIMG_0540.JPG C2 sets fade-in time. Disadvantage: needs pulse tranasformer (10 cent upwards from China). The UTJ circuit is from around 1966 or so, For triggering I think most triacs are fine when triggered positive with negative voltage across those. No idea if it dims all LED lights, my cheap Chinese LED bulbs use a capacitor as current limit in series with a bridge with the LEDs in it directly on the mains, no other parts, should work. Wave form drawings should explain. Other disadvantage is the series resistor for the 12V, but it basically only charges the cap, the PNP is a linear current source to charge the cap, not many mA needed You can replace the resistors on the PNP with a pot for brightness adjustment. Circuit resets at each zero crossing of the mains and causes a trigger pulse sooner (brighter) or later (dimmer) in each half cycle. <disclaimer> <end disclaimer> Would a ISDN transformer work as pulse transformer ;-)?
Reply by ●September 27, 20202020-09-27
On Saturday, September 26, 2020 at 4:20:20 PM UTC-4, jla...@highlandsniptechnology.com wrote:> On Sat, 26 Sep 2020 11:33:10 -0700 (PDT), Tabby <tabbypurr@gmail.com> > wrote: > > >On Saturday, 26 September 2020 17:37:43 UTC+1, jla...@highlandsniptechnology.com wrote: > >> On Sat, 26 Sep 2020 17:11:54 +0100, Piglet <erichpwagner@hotmail.com> > >> wrote: > >> >On 26/09/2020 15:56, jlarkin@highlandsniptechnology.com wrote: > >> >> On Sat, 26 Sep 2020 08:54:01 +0100, Piglet <erichpwagner@hotmail.com> > >> >> wrote: > >> >>> On 25/09/2020 18:36, John Larkin wrote: > > > >> >>>> Given that this is an electronic design forum, we should design > >> >>>> something. I could start. Maybe some others can suggest circuits. > >> >>>> > >> >>> > >> >>> I already started - didn't you see my design? > >> >>> > >> >>> piglet > >> >> > >> >> Sorry, missed that one. I'd delete the EMI filter, except with a > >> >> standard dimmer as the starting point, it's free already. > >> >> > >> >> What about ramping down the value of Rt over time? Some variation on > >> >> one of my circuits? NTC thermistor? > >> >> > >> >> Maybe the entire circuit could be one NTC thermistor, one of those > >> >> inrush limiter things. > >> >> > >> >> > >> >> > >> > > >> >Yes, I think Tabby (or someone) suggested an NTC already. > >> > > >> >piglet > >> > >> Maybe heat sink it to a chunk of aluminum or two to slow down the > >> turn-on? > > > >With 20w of load a biggish one or 2 may be slow enough as is. Heatsinking it would require great thermal contact to be effective in slowing interior heat-up, most THs aren't a good shape for that. Laser slice them? :) > > My wild guess is that a bit of heat sinking would slow it down. One > NTC would sure be simple, but dramatic home theatre lighting may have > crucial timing requirements. > > > > >You might be able to slow it further with a series cap. It takes the LED closer to the point where it dims, ie lower mains v, and Xc + Rth is going to be larger at any time during warm up. And if you really must you could slow it yet again with a PTC Thermistor across the bulb. > > NTC-PTC voltage divider. Interesting.That is fun! Do NTCs, PTCs have lifetime, number of uses limits? (I know I could search on DK... but that's work. :^) George H.> > > > >There are so many ways it can be done. And Ricky is getting snipey again. > > Again? > > > > > > > >NT > > > -- > > John Larkin Highland Technology, Inc > > Science teaches us to doubt. > > Claude Bernard
Reply by ●September 27, 20202020-09-27
On 9/27/2020 1:40 AM, Jan Panteltje wrote:> On a sunny day (Sat, 26 Sep 2020 14:42:14 -0700) it happened > jlarkin@highlandsniptechnology.com wrote in > <badvmftp4m6r9vfsbvt0a7u9a28og9sm9j@4ax.com>: > >> The data sheet prohibits me from copying or printing it. OK, deal. > Here is my take, untested: > http://panteltje.com/pub/triac_trigger_r_IXIMG_0540.JPG >I see you are still stuck in your old ways. Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●September 27, 20202020-09-27
On Wednesday, September 23, 2020 at 12:08:15 AM UTC-4,> I need a simple circuit design for a slow fade-in AC dimmer. In a dark theater, suddenly turning on the lights is a somewhat unpleasant experience. I want a simple circuit compatible with 110 volt dimmable LED lights that will slowly ramp the light output over a period of about 5 seconds or so. I have found a number of simple designs that would work for 12VDC LEDs, but none for 110VAC dimmable LED lights.Can't you just use an Alexa (Amazon Echo) compatible light bulb and run a quick script? 10%..., 20%..., 40%..., 100% Each bulb is addressable.
Reply by ●September 27, 20202020-09-27
On 27/09/2020 16:40, George Herold wrote:> On Saturday, September 26, 2020 at 4:20:20 PM UTC-4, jla...@highlandsniptechnology.com wrote: >> NTC-PTC voltage divider. Interesting. > That is fun! > Do NTCs, PTCs have lifetime, number of uses limits? > (I know I could search on DK... but that's work. :^) > > George H.Yes, the shadow mask degaussing coil around CRT color tubes was often fed by a PTC/NTC thermistor combo. Mostly reliable but switching on and off repeatedly before they had reached thermal equilibrium was said to kill them. piglet
Reply by ●September 27, 20202020-09-27
On Sun, 27 Sep 2020 17:32:27 +0100, Piglet <erichpwagner@hotmail.com> wrote:>On 27/09/2020 16:40, George Herold wrote: >> On Saturday, September 26, 2020 at 4:20:20 PM UTC-4, jla...@highlandsniptechnology.com wrote: >>> NTC-PTC voltage divider. Interesting. >> That is fun! >> Do NTCs, PTCs have lifetime, number of uses limits? >> (I know I could search on DK... but that's work. :^) >> >> George H. > > >Yes, the shadow mask degaussing coil around CRT color tubes was often >fed by a PTC/NTC thermistor combo. Mostly reliable but switching on and >off repeatedly before they had reached thermal equilibrium was said to >kill them. > >pigletWere they separated or thermally coupled? -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●September 27, 20202020-09-27
On Sunday, 27 September 2020 02:56:49 UTC+1, bitrex wrote:> I think a thermistor might work with some cheapo LED bulbs but the > good-quality ones have an integrated buck converter that likely has some > undervoltage lock-out on the rectified mains input.why would anyone design that into an LED lamp? What for? NT
