[Discover] Lessons In Electric Circuits http://www.ibiblio.org/kuphaldt/electricCircuits/ (tutorial reference hardware electronics)
 [Discover] Electronic Schematics for Hobbyists http://electronics-diy.com/electronics/index.php (diy circuits reference hacks)
 [Discover] LEDCandle http://www.r4nd0m.com/Candle.html (led projects electronics diy)
 [Discover] Design with Microcontrollers: Simple PWM DC motor control using MOSFET H-Bridge with AVR ATmega8 http://www.dharmanitech.com/2008/11/small-dc-motor-control-by-pwm-method.html (pwm avr microcontroller circuits)
 [Discover] Capacitance / Touch Switch Circuits free electronic circuit links http://www.discovercircuits.com/C/capacitance-sw.htm (circuits capacitance diy switch)
 [Discover] 4QD-TEC: Electronics Circuits Reference Archive Index http://www.4qdtec.com/index.html?Home=+Home+ (circuits engineering diy howto)
 [Discover] uC Hobby " Blog Archive " Arduino Sound Part 2: Hello World http://www.uchobby.com/index.php/2007/11/14/arduino-sound-part-2-hello-world/ (circuits avr hardware sound)
 [Discover] Perry Hoberman: Relay Circuit Diagram http://interactive.usc.edu/members/phoberman/archives/007581.html (relay hardware diagram diy)
 [Discover] Lessons In Electric Circuits http://openbookproject.net//electricCircuits/ (electric circuits resources tutorial)
 [Discover] Bowden's Hobby Circuits http://ourworld.compuserve.com/homepages/Bill_Bowden/ (electronics circuits projects howto)
 [Discover] Analog Technologies, Semiconductors, Digital Signal Processing - Texas Instruments http://www.ti.com/ (analog company companies manufacturer)
 [Discover] STMicroelectronics - Product Family http://www.st.com/stonline/domains/buy/samples/index.htm (circuits parts electronics)