Don't do this. Most ICs can only withstand input voltages of 0 (GND) to VCC at their input pins, and if VCC is zero (not connected) no voltage must be present on any input pins.I'm confused - not uncommon - but more so about where power is coming from after connecting a Pi Zero 2W to a breadboard with I2C to a ADS1115 board and SPI to a MCP3008 board. Both boards work fine, their operation isn't a problem, but I thought I would save a bit of drain on the Pi, so I added a switch to switch the 3.3V line from the Pi (physical pin 1) coming into the breadboard so I could turn the ADC chips off when not in use.
Statistics: Posted by fchk — Fri Oct 24, 2025 5:08 am