NPN transistor Key with external voltage source

Hi there, I am having problems with using NPN transistor as Key with Nvidia Jetson Nano 2GB. Problems do not occur while testing transistor key with LED, controlled through base with Jetson GPIO.

However, my task is to control series of LED, connected to external source (9V battery), I have connected battery ground and GND from Jetson in order to have common ground, it does not apper to work, even when i try to controll it directly from 3,3V or 5V pin. What appears to be wrong?

Thanks in advance


This topic belongs in the Jetson category, I have moved it to the correct forum for help.

I can’t say for certain, but a bipolar transistor (which is what an NPN transistor is) will draw significant current. This might be more than the GPIO can handle. A better choice might be a FET or with a buffer chip (a buffer could source more current and power the transistor; perhaps the right buffer could power the LED without a transistor; a linear amplifier would be a waste/overkill, but could also do the job if adjusted).

Not sure what the issue may be, but you could try TLC5947 or TLC59711 from TI. Adafruit has pre-made boards and CircuitPython support.

Or Share the schematic

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