Here are some useful articles on electronics and microcontrollers.
Digital I/O expansion methods.
The Arduino shiftOut() function can simply control many different serial interfaced chips. Find out how it works and how fast it operates.
A tutorial on using the ADS1115 precision 16 bit ADC for low power use.
Learn how to use the TP4056 properly. There's a right, and a wrong way, to use it to safely charge Lithium Ion batteries.
The MCP4922 chip is an SPI interfaced 12 bit DAC but how fast can it go? Find out here.
The MCP4725 chip is a 12 bit DAC with memory that outputs voltage that you can use for many dfferent purposes. Find out what they are in this page.
The MCP4728 chip is a four channel 12 bit DAC, with memory that outputs voltage that you can use for calibration, anywhere you want a fixed voltage.