Overheating Shift-Register(74HC595) I am working on a project where I need to use around 50 LED's connected to an Arduino UNO board. To begin with i worked on the tutorial provided by Arduino (https://www.arduino.cc/en/Tutorial/ShiftOut) to connect two shift registers(74HC595). Everything works fine, but the shift registers get very hot in just a few minutes. Is this normal?
I can only think about two things:


(least probably): the entrance (VCC) voltage is too high.
(most probably): the resistors to the LEDs are (too) low .. Recalculate the values and check the max amperes which can be handled by the output pins of the shift registers.