I want to control a 4-digit multiplexed 7-Segment + Decimal Point Display (SH5461AS).
However, all the tutorials I have found
- Raspberry: https://raspi.tv/2015/how-to-drive-a-7-segment-display-directly-on-raspberry-pi-in-python
- Arduino: https://www.instructables.com/4-Digit-7-Segment-LED-Display-Arduino/
- Question on Rasp-pi SE: Multiplexing 4-digit 7-segment display is flickering
don't use transistors but use GPIO's as GND or VCC thereby controlling the display without transistors.
My question is: is this method without transistors safe? (of course with resistors) An electrical engineer friend of mine suggested that by using an GPIO as GND the current might flow through the microprocessor itself therefore potentially creating dangerous current in the MC.