Schematic to PCB trace route

[ThomsCircuit]

did I wire this correctly?
The resistors (R2+R6) connected to pad 3 of LM311 are joined but in the PCB ive got them connected differently. A member mentioned it to me a while back but at the time i did not quite understand his concern. I do see it now so im wanting to know if this is ok or how should have i wired this up.

 

[ThomsCircuit]

in a somewhat related question if i wanted to make this Dusk to Dawn circuit a Dawn to Dusk (reverse) I would swap pins 2 & 3 like this? I read that this is how it is done but the discussion was referring to a different IC

 

[AnalogKid]

I count six crossed nets. If that is a two-sided layout, please use different colors for each layer.

ak

 

[ThomsCircuit]

I count six crossed nets. If that is a two-sided layout, please use different colors for each layer.

Ok will do.

 

[ThomsCircuit]

 

[rjenkinsgb]

You have some crazy spacing around the 120V AC connections - there should ideally be 5mm separation between any such AC pads or tracks, and any other circuits. Plus decent space between L / N / Load connections.

 

[ThomsCircuit]

You have some crazy spacing around the 120V AC connections - there should ideally be 5mm separation between any such AC pads or tracks, and any other circuits. Plus decent space between L / N / Load connections.

Gosh, i did not know about the spacing. I added that at the last minute to utilize the available pole on the relay. Poured some wide tracks too. I really have no plans to use that side so ill make changes to the PCB and improve the spacing. I did recently open up a transformer (wallwart) and observed the AC input tracks were pretty close together.

 

[ThomsCircuit]

I moved the pours to the bottom layer. Isolated the tracks from any other tracks and pours. Its 5mm in some places but its 3 in a few others. Thank you.

 

[ThomsCircuit]

You have some crazy spacing around the 120V AC connections - there should ideally be 5mm separation between any such AC pads or tracks, and any other circuits. Plus decent space between L / N / Load connections.

do you think you could address my initial questions on #s 1&2

 

[rjenkinsgb]

I don't see anything obviously wrong with the inputs in the first circuit?

However, I've never seen pins 5 & 6 linked - that's not needed; those pins are only used if you need to trim the input offset, by adding a preset and resistor.

You can swap the inputs, as long as you leave R5 connected to pin 2, for positive feedback (hysteresis). Swapping that could cause oscillation.

 

[ThomsCircuit]

I don't see anything obviously wrong with the inputs in the first circuit?

However, I've never seen pins 5 & 6 linked - that's not needed; those pins are only used if you need to trim the input offset, by adding a preset and resistor.

You can swap the inputs, as long as you leave R5 connected to pin 2, for positive feedback (hysteresis). Swapping that could cause oscillation.

Thank you. I completed a PCB. It did not work at first so i did the easy thing and replaced the IC with one from a different batch. That fixed it, HOWEVER... I decided to check another from the 1st batch and that also did not work. Swapped it back with the previous and WTH! that IC no longer worked. So I had one more IC from the 2nd batch and its running now but what happened?

When I say did not work:
When powered up it engaged the relay. adjustments , light, dark had no effect on the circuit.

Top IC is from my older batch

 

[ThomsCircuit]

I have set up a bread board to test these ICs
My IC is now working as the circuit functions normal
I tried a few of the others and they give in-consistent results.
Lesson Learned

 

[Nigel Goodwin]

Thank you. I completed a PCB. It did not work at first so i did the easy thing and replaced the IC with one from a different batch. That fixed it, HOWEVER... I decided to check another from the 1st batch and that also did not work. Swapped it back with the previous and WTH! that IC no longer worked. So I had one more IC from the 2nd batch and its running now but what happened?

When I say did not work:
When powered up it engaged the relay. adjustments , light, dark had no effect on the circuit.

Top IC is from my older batch
View attachment 142068

Those IC's look suspiciously different?, depending where you got them either (or both) could be fakes - various dodgy Chinese companies relabel any old faulty chips they can get and sell them on as completely different chips.

The top one in particular looks like it may have been sanded off, and reprinted.

I bought a load of LM335 temperature sensors, just to keep in stock, and when I came to need one I couldn't get the circuit to work (battery temperature sensing for a PIC Li-Ion charger circuit). So I removed it, and tested it on one of my Chinese component testers kits, to find it was an NPN transistor (with low gain), so I checked all the rest, and they were a mix of NPN/PNP transistors, FET's, and even SCR's (probably all out of spec. rejects) - not a single LM335.

So I ordered some LM335's from RS Components, which worked perfectly of course - so I tried one in the component tester (knowing full well it wouldn't test as an LM335), and it didn't test like any of the previous fake ones.

 

[ThomsCircuit]

Those IC's look suspiciously different?, depending where you got them either (or both) could be fakes - various dodgy Chinese companies relabel any old faulty chips they can get and sell them on as completely different chips.

The top one in particular looks like it may have been sanded off, and reprinted.

That bottom IC logo doesnt even look like Texas. This is the first and probably last time i will buy a component from ALIExpress. Your not gonna believe how the seller sent me the parts. And yes, thats STATIC CLING WRAP.

 

[For The Popcorn]

One place I can strongly recommend for high quality parts is Tayda Electronics, located in Thailand with some warehousing in the US. Their pricing is good, shipping quick and affordable, with a decent range of parts.

When they did ship me the wrong parts (right angle vs straight terminal blocks), the quickly sent replacements at no charge.

 

[ThomsCircuit]

One place I can strongly recommend for high quality parts is Tayda Electronics, located in Thailand

Agreed. I sent them a message asking why their shipping is so high now. I bought from them for years for 5-7$. Now its 15$

 

[ThomsCircuit]

I put on my "hat of reasoning" and used my debate skills to get the seller to admit his IC chips were defective.
The platform at ALIExpress has requirements when requesting a refund. I uploaded images , videos, and provideded all the documentation that proved the chips were defective and i deserved a refund. I have to admit i spent more time on this than anyone else would have but i wanted to accomplish two things. One: that I was right. and Two: that it is important that the seller and buyer can trust each other. Well either my relentless chat session caused him to just give up or he actually believed me. I told him i know the world can be a cruel place but I wanted these chips to work just as much as he did. With some facts and reasoning he ultimately had no choice to admit that my video tests proved that his IC chips were indeed defective.
Needless to say, regardless of the outcome, that took way more time and energy that it was worth so I dont think I will be buying anymore products from AliExpress

This snapshot is after 3 days of chat