Hi, this is my first post. I read all voltage divider threads.
I'm thinking of getting 5v from a 12v DC source. Now I've read the first 2 books of All-in-one Electronics for Dummies, and a bit of reading on the internet, so I don't know much yet. The question:
There's voltage regulators that are made to step down a 12V source to 5V, but they lack severely in mA. So I research voltage dividers, which I've met in my readings, but I'm not sure how the amperage would be calculated, the usable amperage. I think a lower value would mean more amps for the load, but with this: http://www.sengpielaudio.com/calculator-ohm.htm (and http://www.calculatoredge.com/electronics/voltage divide.htm) lower values require higher wattage, thats where the trouble starts, what is amperage dispensed by the resistor and what is amperage left over for all the juicy bits that will become the load? (This entire question is at date hypothetical, but soon I'll use it) Is it more efficient to use a 7805 regulator potentially delivering more than 1A, or a 470R (which I can get a high wattage package of) and then a trimmer 0.1W 470R potentiometer (set it to 335.71, measure with multimeter until its 5V) but if I go below 250R (?) I'll burn my trimmer potentiometer. Any lower values of resistors require more than 0.1W on the potentiometer. And I'm guessing go as low as you can go for highest usable load current, but then again I'm thinking, well its like a water pipe, and if one part is thin, thin is as high as you can go? Regulator 78L05 delivers 100mA.
So maybe I should add: I wan't to experiment with digital electronics, what type of load do I need to be able to carry, and if there is transistors for the load, can I use a second 12DC power source to drive only the load?
OK, thats more than one question...
PS I bought 8 12VDC psu for basically nothing, thats why the "obsession" with 12VDC
I'm thinking of getting 5v from a 12v DC source. Now I've read the first 2 books of All-in-one Electronics for Dummies, and a bit of reading on the internet, so I don't know much yet. The question:
There's voltage regulators that are made to step down a 12V source to 5V, but they lack severely in mA. So I research voltage dividers, which I've met in my readings, but I'm not sure how the amperage would be calculated, the usable amperage. I think a lower value would mean more amps for the load, but with this: http://www.sengpielaudio.com/calculator-ohm.htm (and http://www.calculatoredge.com/electronics/voltage divide.htm) lower values require higher wattage, thats where the trouble starts, what is amperage dispensed by the resistor and what is amperage left over for all the juicy bits that will become the load? (This entire question is at date hypothetical, but soon I'll use it) Is it more efficient to use a 7805 regulator potentially delivering more than 1A, or a 470R (which I can get a high wattage package of) and then a trimmer 0.1W 470R potentiometer (set it to 335.71, measure with multimeter until its 5V) but if I go below 250R (?) I'll burn my trimmer potentiometer. Any lower values of resistors require more than 0.1W on the potentiometer. And I'm guessing go as low as you can go for highest usable load current, but then again I'm thinking, well its like a water pipe, and if one part is thin, thin is as high as you can go? Regulator 78L05 delivers 100mA.
So maybe I should add: I wan't to experiment with digital electronics, what type of load do I need to be able to carry, and if there is transistors for the load, can I use a second 12DC power source to drive only the load?
OK, thats more than one question...
PS I bought 8 12VDC psu for basically nothing, thats why the "obsession" with 12VDC