Daren - yes you could eliminate the upper circuit and provide an outside source for Vcc. You would have to keep R3 in order for the PIC to monitor the AC zero crossing. As for hooking up the load to JP2 - your gif is correct. The Hot In on the circuit is used for the Vcc production and is used for zero crossing detection. Hot would also go to one side of the load. The other side of the load would go to "Hot Out" - which goes to the Triac. The other side of the Triac goes to Neutral (Return(White)) - per your extra line on the gif. Therefore, the current (voltage - whatever) would flow through the light, but stop at the Triac when it was off - therefore a dead end - no current flow. As you turn the triac on, the current would be allowed through the Triac to Neutral (Return) which would allow current through the light causing it to produce illumination. Hope this helps! David V. Fansler Network Administrator TriPath Imaging, Inc. (Formerly AutoCyte, Inc) 336-222-9707 Ext. 261 dfansler@autocyte.com Now Showing! www.mindspring.com/~dfansler Updated September 23, 1999 -----Original Message----- From: Darren King [mailto:darren.king@SYMPATICO.CA] Sent: Thursday, December 09, 1999 3:24 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: Microchip Appnote Dimmer Problem. << File: 40171a10.gif >> Could I eliminate the Vcc Circuitry? That would make it much simplier for learning and just use some batteries or another wall wart. How would that effect the circuit in regards to zero crossing? How can the TRIAC work if I hook the load up between Hot IN and Hot OUT? I've read everything and I'm just having trouble understanding why there are 3 wires at JP2. One of them has to be duplicate so to speak. If the connection was made between Hot in and Hot Out. So Therefore. White is as we know White. Hot In is I guess Black... The circuit goes Hot Out is where the load is connected between the triac and then back to Hot In. Wow is this schematic bad. The Jumper will have to have 2 wires connected to pin 3 and 1 on JP2. Thats what confused me so much. Here is what I think the schematic should look like. In otherwords the Load or the light bulb is connected directly to mains, but because of this stupid jumper its all very confusing. Is this correct people? I made a diagram and its quick and ugly but it does show the important Mains connections. Darren King ----- Original Message ----- From: Mark Willis To: Sent: Thursday, December 09, 1999 2:24 AM Subject: Re: Microchip Appnote Dimmer Problem. > Ummm... Fun one > > Fansler, David wrote: > > > > Darren - I do not pretend to be an expert - but here is what I see. > > 1. The schematic does not totally match the article > > 2. The load would go between Hot Out and Hot In. > > I don't like the "hot out" term at all; Originally I was misled, here - > I'd expect the load to go between Hot Out and Return, given that > terminology! Hot In is power from the power grid, and, Hot Out is > pulled towards Neutral/Return from Hot In by that Triac, to light the > bulb - so I'd have called that Lamp Return instead, or something like > that. So yep, David's right, and this is just plain murky terminology > Not an electrician, I guess? > > > 3. You would supply a Neutral (white wire) to Return. > > 4. You would supply Hot (balck wirefrom power company) to Hot In > > 5. Ground (green) is a good idea. It can be tied to Neutral (which is > > done in US breaker boxes). > > Definitely a good life-saving idea. > > > 6. Vcc is generated by the circuit above the PIC (RV1, R1,2, C1-3, > > D1-3) > > 7. I would take JP1 to be an external input to allow control of the > > circuit by an outside source (another PIC, automation system, etc.) > > For safety, I'll add this: If you're going to use JP1, please DO verify > that "Neutral" isn't hot with respect to the Ground line, before or > during installation; If it is and you connect a switch pair to J1, > touch a lead on that & grab something that's grounded, and you can be > killed. So - please be a little careful there! > > Probably a good idea to verify that anyways, I've seen a few mis-wired > houses. (Some with 3-prong outlets throughout the house, none having > ground wires attached, almost bought that place... Would've run ground > wires soon!) > > > 8. While simple, a fair warning is given in the article that this > > circuit has no isolation from the AC main and therefore can bite you! > > 9. If used for lighting purposes, this circuit will produce filament > > hum at low light levels (larger filaments hum more) A large choke in line > > with the load will kill the hum. > > Have it hum "Singing in the rain" for us Seattle area webbed-footed > folks? > > > David > > I'll add another finnick: I just plain *detest*, dimmers that come on > "Full Bright" when the light's "off". BAD idea; I lose my night vision > so as I later walk down the hall, I step on the cat & get bit & > scratched, trip on the cat scratching post, step on the sharp metal > piece the cat knocked off the shelf and bleed on the carpet, and by then > I'm getting "displeased"... With Full On, I get far more light than I > want or need, it wastes energy (as I dim the light way down & leave it > on all night, instead of turning the light OFF, due to the huge > annoyance of losing night vision) - and it's really hard on the bulb! > > I'd have the bulb come on at 10% or so, and ramp up fast if the user > holds down "Brighter", but not full on to start with; Ick. I've heard > the excuse, "But - full on, instantly, will scare a burglar worse"; I > seriously doubt it, a sane burglar is going to be FAR more concerned > about an occupant turning the light on to 20% - so they still have night > vision, and can still see to chase the burglar, or to get into position > inside the place to hold them for police, far easier than with the > lights coming on full brightness - so the occupant's Blinded completely, > I'd think. > > If you blow a bulb up, that might spook the burglar more; Why use a > dimmer circuit to blow bulbs up, though? Use it to extend bulbs' life, > instead! > > Mark > > > -----Original Message----- > > From: Darren King [mailto:darren.king@SYMPATICO.CA] > > Sent: Wednesday, December 08, 1999 2:44 PM > > To: PICLIST@MITVMA.MIT.EDU > > Subject: Microchip Appnote Dimmer Problem. > > > > http://www.microchip.com/Download/Appnote/Category/rDesigns/40171a.pdf > > > > > > I have looked at the above 100 times and I'm still confused. I don't really > > want to build this circuit without understanding it. I really hope somebody > > could help with this one. I'm not familar with the Hot in - Hot Out -Return > > (White). When I see White I know what that means. So which of the hot in > > and hot out is supposed to be the black? Is the green wire used? Does the > > load hook up between the Hot Out and the Return? What is Vcc supposed to > > be? Is this where I hook up the load? What is RV1? As you can seem I'm > > not an electronics wiz, but understanding this would help out greatly. As > > you can read, I'm really lost. > > > > Darren King > > -- > I re-ship for small US & overseas businesses, world-wide. > (For private individuals at cost; ask.) >