tutorial-power-supplies is a tutorial about how to choose and what consider when using a power supply, building a simple power supply out of batteries, common power supplies, and commercially available power supplies.
There are a lot of power supplies to choose from.
Electrical power supplies transmit power, which is the product between voltage and current. They provide a fixed voltage, and they transmit as much current as needed by the device to comply with the power requirements.
Power supplies usually connect to mains voltage
- Input voltage
- Output voltage
- AC or DC
- Current rating
- Physical connector
Power supplies need an input. They usually connect to a mains outlet. In USA, mains outlets are 110 XX volts AC. In Japan, they are 120 XX volts AC. In most of the world it is 220 or 230 volts AC. The corresponding XX do a table instead of plain text.
AC or DC
In the case of DC, you need to know if the connection is center-positive, or center-negative. The barrel that transmits the output of the power supply consists of an outer conductor and an inner conductor.
A center-positive power supply outputs the voltage on the inside and ground on the outside.
A center-negative power supply outputs the voltage on the inside and ground on the outside.
There are several diameters of barrels. XX Check the 1Spot and research about propietary ones if any. Remember the PROCO Rat and EHX Big Muff ones.
Voltage ranges, overheating, common mistakes
Power supplies out of batteries
Voltage regulators are integrated chips that consist of three terminals:
There are several flavors
Guitar effect pedals 9Vdc center negative
Synthesizers 9Vdc center positive
Propietary connectors, Apple Magsafe and Magsafe 2, Apple Lightning.
Power through USB, USB-C Arduinos, cellphones
Commercial alternatives and examples
Truetone 1Spot power supply
Laboratory power supplies
This tutorial was made possible by the author's research residency at NYU ITP during the 2017/2018 academic year.
- Bernardita Moraga, for letting me fill her house with power supplies.
- Víctor Montoya, for teaching me electricity, physics, and soldering.
- Ángel Abusleme, for being an excellent mentor.
- Guillermo Montecinos, for all the collaborations we have had over the years.