I'm trying to control RGB strip used in 7 segment display with an arduino via transistors. the following image illustrates the schematics even though i didn't put the exact resistors values the configuration is a common anode when i control the segments with pwm it works but when i try to PWM the positive side (Transistors Q4, Q8 and Q10 in the image) all i get is fully off or fully on
My crystal ball says your 7 segment display needs 4 to 5V with voltage drop on the cathode segment side and you show 12V.
So when you enable Q1 they are burning up bright and something must be getting hot.
Make sure the segment bits have 100~200 in series (depending on color) or so and then R2,5,7= 600 Ohms
- 10% of 7 segments @10mA?20mA? so 70 (or 140mA if huge) * 10% or 4.3V/7mA = 600 Ohms or so.
oh-oh my crystal ball is getting fuzzy like your logic diagram.... over
I see you have some unknown LEDstrip Current 2.4A per 5meter?? or ?
If a Ledstrip draws 2A at 12V equiv to 6 Ohms then you need a FET or the base current must be 1/20th or more so R2,R7,R8 must be 20x bigger or 120 Ohms which draws too much power for a 1/4 W resistor. So get a 50 mOhm or less Nfet for low side switch or Pch FET for high side switch.
tons of examples on this forum... search LEDstrip driver
it turns out that the problem was me trying to use hardware PWM in arduino analog pins which is not supported. thank you all for your time