Voltage Regulator Heating Problem when using 12 8x8 LED modules


I am running 12 8x8 LED modules for message scrolling using a breadboard Arduino Uno. The 9 volt input voltage is dropped to 5 volts using an L78O5CV linear voltage regulator.

When the Arduino is running without the display on, the linear voltage regulator is very slightly warm to the touch. But when the LED modules are running the regulator gets very hot.

Does anyone know why this is and what I can do to eliminate the problem? (I am not exactly sure how hot is too hot.)

Thanks very much in advance.


That's a lot of current draw. Get a good 5V power supply, one that can supply 4A.

Or if for some particular reason, you insist on using 9 V, get one of the readily available switchmode "buck" regulator modules.

Great! Thanks very much.