Triode
Well-Known Member
**broken link removed**
I'm planning to try making an LED matrix using this diagram. My question is, will there be an issue if one of the shift registers is all on (11111111) when the sinking transistor is active? The guy has a video of it working, but the LEDs are rated as 3.5v 20mA, and the shift register data sheet says it can dissipate 500mW. 8 LEDs x 20 mA x 3.5v = 560mW > 500mW. Is it just that the small difference doesn't matter? Or is it perhaps that since it is multiplexed they are usually not on for very long?
I'm planning to try making an LED matrix using this diagram. My question is, will there be an issue if one of the shift registers is all on (11111111) when the sinking transistor is active? The guy has a video of it working, but the LEDs are rated as 3.5v 20mA, and the shift register data sheet says it can dissipate 500mW. 8 LEDs x 20 mA x 3.5v = 560mW > 500mW. Is it just that the small difference doesn't matter? Or is it perhaps that since it is multiplexed they are usually not on for very long?