An opto-coupler is a device that can be used to electrically isolate two circuits, so that a voltage spike or other problem on one side will not destroy the circuit on the other side. A common use for them is when you want to interface a computer to an AC-powered device, such as a light or a motor. Usually, the opto-coupler will not be used to control the device directly, and instead will just transfer a signal from one circuit to another.
Using an Optocoupler – [Link]
The history and technology in batteries by Jeri Elsworth. This is part of A – Z electronics series sponsored by adafruit.com
Batteries – A to Z of Electronics… – [Link]
Jimmy Proton writes:
In this instructable i will teach you every thing you would ever need to know about the 555 timer IC. If you already know about the chip you could check out my slide show titled “47 projects to do with a 555” it will teach you every basic project to use a 555 with, its great for beginners!
Learn about the 555 – [Link]
Start making mistakes if you want to learn electronics. [via]
Secret to Learning Electronics – [Link]
PWM circuits are fun. You can use them to dim LEDs, control the speed of fans and motors, control the power going to a thermoelectric cooler, or control the power going to pretty much anything you want. Just make sure that you don’t exceed the maximum voltage rating of your device. The video explains it all.
Pulse Width Modulation (PWM) tutorial – [Link]
Bill uses a replica of the point contact transistor built by Walter Brattain and John Bardeen at Bell Labs. On December 23, 1947 they used this device to amplify the output of a microphone and thus started the microelectronics revolution that changed the world. He describes in detail why a transistor works by highlighting the uniqueness of semiconductors in being able to transfer charge by positive and negative carriers.
How the world’s first transistor works - [Link]
This is a Java applet that demonstrates the series resonance of a RCL circuit. You can control various aspects of the circuit using the setup menu to catch resonance. This animation is great for demonstration purposes, or simply fast C and L finder when circuit needs to be tuned for resonance. [via]
Animated interactive series resonance circuit applet – [Link]
ladyada.net has write a new article on how to use LEDs for people making their first steps on electronics. It talks about LED polarity, the various kinds of LEDs, what are LEDs used for, changing the brightness with resistors, changing the brightness with voltage, learn how to calculate the current limiting resistor etc.
How to use LEDs introduction- [Link]