74HC595 seems to be a popular way to drive LEDs, so I’m going to get a few of those at Jameco. However, I’m overwhelmed at the vast selection of LEDs. How do I know which ones are suitable to be driven directly by the 74HC595 ? Thanks!
Any of the small 3, 5 or 10mm LED’s should be fine. Just check their current draw and voltage to make sure it is in spec with the 74HC595.
yes, the 595 is a thinking chip, it will not drive heavy loads
it has a max output per pin @ 20ma which is fine for most leds but the whole chip can only take about 70ma (this is absolute max on the datasheet, not recommended)
some of the smaller leds will take less power, and some colors will take less power (ie red takes less than green or blue) so watch your spec’s and choose what you would like
Do not forget proper resistor !
(5 volts - LED forward voltage) / LED current