~ Early Web Links ~

Circuit Sage offers free design routines and tools for analog and RF circuit engineers, covering topics like PLL design, LNA/PA design, impedance matching, bandgap references, and transmission lines. The site provides Mathcad-based calculation routines that serve as practical references for IC and wireless circuit design work.

Jedaler's Electronics Page, built by JaKab-Daniel, is a curated link collection focused on circuit schematics, microcontrollers, RF antennas, robotics, and hobby electronics projects. Visitors will find references to PIC microcontroller resources, Tesla-related circuits, xenon flash designs, and free energy machine plans alongside general electronics archives.

Mostly DIY RF is a specialized resource for amateur radio builders, offering PCB kits and detailed documentation for RF circuits including IF amplifiers, low-pass filters, VFOs, crystal filters, and MMIC amplifiers. The site covers designs by well-known ham radio engineers like Hayward and Kopski, making high-performance transceiver building accessible to hobbyists.

Created by Richard Torrens, founder of 4QD Ltd, this extensive archive covers a wide range of electronics circuits and design information, from audio and motor control to oscillators and power supplies. Built originally as a subscription club and now freely accessible, it emphasizes discrete component design for a solid grounding in fundamental electronic principles.

Phi's personal digital garden covers a range of technical and creative interests including electronics, music, DIY, mathematics, physics, and railways. A cozy old-web style homepage with an 88x31 button for linking, inviting visitors to explore whatever useful or interesting content Phi has cultivated here.

DMX512.com is a technical reference hub dedicated to entertainment technology, covering stage lighting, audio, communications, MIDI, show control, and power systems for theatre production. Named after the DMX512 lighting control protocol, the site organizes resources across multiple categories including net resources, reference materials, and even accident reports relevant to technical theatre professionals.

Bitstream Technologies curates an extensive directory of electronics resources spanning circuit archives, DSP tools, embedded systems, robotics, PCB design, and IC information. A well-organized link library for engineers and hobbyists, covering everything from FPGA design tools to repair and test equipment references.

SchematicsForFree is a volunteer-run archive offering free electronics schematics, circuit diagrams, and service manuals covering audio, video, automotive, and test equipment. Updated regularly since 2022, it embodies the original open-sharing spirit of the web, providing hard-to-find technical documents at no cost.

A comprehensive reference hub dedicated to the Smith Chart, the classic RF engineering tool invented by Phillip Smith of RCA, covering tutorials, software downloads, example charts, reference books, and curated links to related tools and pages. Visitors can explore the mathematical foundations of impedance matching, s-parameters, and microwave design through a well-organized collection of articles, Java applets, and PDF resources.

Tonne Software offers a catalog of free and low-cost electrical engineering programs for Windows, covering filter design, meter scale drawing, great-circle mapping, Smith charts, and more. The site also hosts technical articles and tutorials on topics like speech processing, AM demodulators, and CW bandpass filters, many published or submitted to QEX magazine.