Here are collection of electronic projects  I found on internet. Many of them only contain circuit or schematic, but several is a completed project, including detailed comment, PCB file and even photos. 

The projects listed here are belong to other persons. I just collect and arrange them in my place. Credit for him/her who builds and publishes the projects. Please also notice what the owners say about copyright stuff in their pages.

I noticed that some of the hosting servers linked is not very stable. If you find broken link, please let me know, by dropping a comment.

The Index:

• Radio Frequency (RF) Circuits [7] : 1 2 3 4 5 6 7
• Television and Video Projects [2] : 1 2
• Computer (PC) Interfacing Projects [3] : 1 2 3
• Power Supply Circuits [5] : 1 2 3 4 5
• Telephone and Intercom Circuits [2] : 1 2
• Filter Circuits [1] : 1
• Measurement and Testing Circuits [4] : 1 2 3 4
• Solar Power Circuits [1]: 1
• Remote Control (RC) Circuits [2] : 1 2
• Timer and Oscillator Circuits [3] : 1 2 3
• Motor Control Circuits [2] : 1 2
• Health and Medical Electronic Circuits [2] : 1 2
• InfraRed and IrDA Circuits [2] : 1 2
• Games and Fun Circuits [2] : 1 2
• Security and Alarm Circuits [2] : 1 2
• Automotive (Car and Motorcycle) Electronics [2] : 1 2
• Laser Circuits [2] : 1 2
• Lightning and LEDs Circuits [4] : 1 2 3 4

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Sources of the links:

• www.circuits-city.com
• aaroncake.net
• ee.washington.edu
• www.web-ee.com
• www.electronics-lab.com
• and… lot of individual project sites.