Topic outline
Drawing Symbols
This link is for the IEC (International Electrotechnical Commission) Drawing Symbols.
Transducers and Sensors
This is a very long and comprehensive video on Resistance Temperature Detectors.
I recommend it to anyone who is working in an area that require temperature detection.
This video explains how to use a semiconductor based temperature sensor. At run time of 10 minutes it's an efficient use of time for an overview of these sensors.
This video is an introduction to using Infrared sensors for proximity using an arduino nano.
This brief but succinct article will give you a basic understanding of optocouplers