You’d be surprised at how much some of this is new to me. Yes, it applies concepts I learned 30 years ago, but unless I have one on hand (and I don’t think I do), you will almost certainly build an LED circuit using a constant current source before I do - my degree is in electrical engineering but I never actually worked as an EE, what little I did do goes back to just the first year after I graduated in 1988. After that - electronics is just a hobby foir me, and mostly all digital at that, and I’ve been a computer guy. I managed to pick up a collection of electronic magazines from 200 to present, I’m up to 2007 now, so I am aware of many of the newer things out there - plus things like Dave Jones’ EEVBLOG Youtube channel has lots of good info, his fundamentals stuff turned the light bulb back on and wouldn’t be bad for someone trying to learn - if you can take his voice. Doesn’t bother me, but he’s a small Aussie guy so in addition to the accent his voice is somewhat high pitched. My GF thinks his voice sounds like nails scraping on a chalk board and leaves the room if I watch one of his videos.
I had a quick look at Dave Jones’ videos. Very entertaining but I think I would be exhausted if I watched more than a few minutes at a time![swg] Most of his stuff seems to be way beyond what I need to know, or want to know.[D)]
Yeah, he is all over the place, from fundamental stuff to advanced topics. The Mailbag segments are fun, people send him all sorts of crazy stuff. Lots of fun when he has his kid on with him/ Pretty amazing that he started with a workbench in his garage while he still had a regular dya job and now owns space in two different buildings with a huge lab and an office. Oh, look up the ones on the Indiana Jones train set for model railroad content - he’s a bit of a model railroader as well. Seems a hobby shop near him closed up and since he’s both a train buff and an Indiana Jones fan (and a HUGE Back to the Future fan), he managed to get them to let him take the layout so long as he could remoove it from the property. Kind of a simplistic waterwings plan but it has scenese from all the Indiana Jones movies including lots of lights and animations - like mine carts from the second one, the big flying wing fight with the giant German guy from the first one, etc.There are a couple of older videos where he goes over it trying to figure out how he can take it apart to fit in a van, then there’s one where he cuts it apart, and there’s a more recent one where he started putting it back together again (only a few year have elapsed LOL. ) He also has a second YouTube channel, EEVBLOG2, where he posts stuff not necessarily of interest to electronics people, and he has several videos there of riding various tourist rail lines in Australia (and one of a huge G scale layout). And being so into science he managed to convince his wife to name their first boy Sagan, and he has a little brother Huxley. Sagan loves trains too. There was another video from about 2 years ago or so, he has a small N scale layout he kept int he lab, one of those pre-formed base things, and he pulled it down and got it running with Sagan.
I have a bunch of LED with resister already built into the wiring. However, the LED is much brighter than I desire. Can I insert another resister in series with the existing LED/resister to make the LED dimmer?
Sure. You could even get something like a 5,000 ohm potentiometer and insert in the circuit on a temporary basis. Adjust the potentiometer until you get the desired brightness, then disconnect it and measure the value of the pot. Replace the pot with a fixed resistor with a value close to that which you measured.
By the way, while you can do the same thing with a plain LED without an inbuilt resistor, it is very risky since it would be easy to run the pot down to too low a value and blow the LED.
Knowing that you are starting with a 12V supply, you could add a fixed resistor so that if the por were accidently turned to minumim it wouldn;t fry the LED, Rarely for hobby use are LEDs too dim, witness all the extra added to dim them down when a 1K resistor is already less than half the LED’s current rating. The final answer would then be the fixed resistor plus the pot reading, instead of just the pot reading with the added bonus of not blowing up the LED because the pot was turned too low.
And it does happen, the other day I wondered why my circuit wasn;t working - I previously had set the current limit on my power supply to a fairly low value, something to protect the previous circuit I was working on, and neglected to turn it back up. The new circuit drew more current, so it was putting the power suppyl into current limit mode and the voltage was dropping well below 5 volts. Though I always try to remember to at least turn the voltage down when shutting things off, I always turn on the power supply with it disconnected from the circuit just in case - wouldn;t do to feed 12V into a 5V chip with an absolute maximum of 5.3V.