Hello,
first 0f all,
I’m university student
professor gave me a assignment
that is Circuit analysis of mk117 (how this circuit runs)
and i have to explain to my class mates
so, I have some questions.
Four green LEDs are connected on the same line, why did you use 1K ohm?
three red LEDs are connected on the same line, why did you use 1.8K ohm?
(Do you have each specific reason to use 1K ohm and1.8k ohms?)
thank you, have a nice day
Average LED voltage drop for red leds is 1.6V, while green leds typically have 1.9-2V drop.
Voltage drop for red leds is 1.6 * 3 = 4.8v
Voltage drop for green leds is 1.9 * 4 = 7.6V
To make sure they receive approx same current, resistor needs to be different.
This is a basic application of Ohms law, you might want to look up some theory on this issue.
You should download and look this over.
There is a lot of good information.
http://www.vellemanusa.com/downloads/EngineeringNote-enu.pdf