ThomsCircuit
Well-Known Member
yes. and thank you so much.I believe you mean square millimetres, not cubic!
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yes. and thank you so much.I believe you mean square millimetres, not cubic!
Could you identify the pins (C B E) for the darlington NPN?
View attachment 135590
in post #118 you can see there are 6 spokes. it was the only way (at this time) that i could get enough spokes around the collector. The emitter still has three on the top pour but gains a fourth on the bottom pour.
yes it is.Hmmm....is this an NPN as low side switch? I don't remember what the schematic showed.
Yes. That is absolutely what i have done.If so, the highest current will be passing thru the collector (connected to the light) and emitter (connected to GND) of the darlinton transistor. So, I would expect that the emitter would be a thermal pad connected to the ground pour, and the collector would be a thermal pad connected to a isolated pour that includes a light terminal pin thermal pad. The base pin doesn't need to be very wide
Im going to try to look this up but i believe any existing track, regardless of its width becomes part of the pour. So if you are referring to the thin track from the collector to the pin, i purposely reduced its size so it would not negate the purpose of the spokes. but i did make them wider for the entire board. default 10, now at 16. And I extended the collector pour area to include the LED.make the red track wider.
I have found this in the pour settings. As of now I can only make settings per project. While it comes in handy for temporary adjustments on pads for a component things like net track widths are per project. But for now I don't mind.For future reference...you can create your own custom Thermal pad with wide spokes so you don't have to manually widen the them.
At the time i was a bit overwhelmed but i then go back and re-read a few posts to spot things i may have overlooked.If the transistor gets too warm during the fade with your device, either C1 or R1 can be increased to reduce the switching frequency.
That was the MOSFET; its dissipation will be highest during the fades.im wanting to know if you were referring to the TIP in the above statement or the mosfet.
That would dissipate roughly 75mW at 5A, with the circuit running on 12V.
That's from reversing the input & output, early on..Ive noticed that when this circuit initializes the light connected to the output comes on at 100%
You know I brag about you guys.Change C3 so its between the control voltage and power, rather than control voltage and ground.
is this what you are referring to? input / outputa bit higher gate capacitance
Ive had this on most of the day with this new setting to C3. It initially works perfect but gradually starts to fails. Its connected to a timer so it auto shuts off after 5 minutes so it does not stay on for long. And, i just have the single led connected. If i attempt to turn it on it begins to hesitate then fades up but fading off is rapid. Eventually it will not respond at all. If i change the cap it works again for a while then starts to fail again.That's from reversing the input & output, early on..
Change C3 so its between the control voltage and power, rather than control voltage and ground.
Hi.You still need to respect the capacitor polarity!