I now have several Pi 3B+, a Pi 4B, and a Pi Zero W. I also have a giant tangle of cables, so I’ve put together a cheat sheet. (This is a “Wiki post,” which means that anyone who’s been around K12Computing for a while can edit it. If you spot errors, have information to add, or want to add info for a Raspberry Pi model that I don’t have, you can edit this post.)
|Model||HDMI||USB||Power Cable||Power Supply||Brown’s recommended power supply|
|Raspberry Pi 3 B and B+||HDMI A Standard||USB A||USB Micro-B||5V 2500ma||https://www.adafruit.com/product/1995|
|Raspberry Pi 4 B||HDMI D Micro *||USB A||USB C **||5V 3000ma||https://www.raspberrypi.org/products/type-c-power-supply/|
|Raspberry Pi Zero||HDMI C Mini||USB Micro-B †||USB Micro-B||5V 2500ma #||https://www.adafruit.com/product/1995|
* The Pi 4 supports two displays, so there are two HDMI connectors, labeled zero and one.
** A design error in the 2019 models of the Pi 4 prevents E-marked USB-C cables from working. The safe approach is to use the official power supply.
† There’s only one USB port for peripherals; it’s USB OTG so it requires either an adapter cable or a USB OTG hub to use standard USB peripherals. To use both keyboard and mouse, you’ll need a USB hub and USB Micro-B to USB A OTG cable.
# The Pi Zero itself consumes only about 100ma with WiFi and Bluetooth off, no keyboard or mouse.
The recommended power supply is over-specified, but it’ll work with your Pi 3, too.
For battery operated projects, it will be best to do some actual current measurements.