The lost transistor & Flashback: Solar xlophone....

The lost transistor?

While conducting historical research for the recent video, I came across references to an earlier iteration of the device apparently created way back in 1933 - a full 14 years before Bell Labs researchers had a working model. What makes the discovery even more compelling and inspiring is the fact that its inventor, Robert Adams, was only 13 years old when he made it. Though no patents or publications were created describing its functionality, Adams is said to have built multiple crystal radios utilizing the device. Though Dr. Robert George Adams passed away in 2006, documents some of his work –

Two different methods of interconnection between the two crystals were employed –

1. By copper wire from a crystal mounted in a crystal cup, the other end of which is connected to the crystal set proper.
2. By direct physical contact (under small pressure) in an assembly of two crystal cup holders with vertical mounting brackets secured to a small insulated base board.

Connections to this small module of two crystals was achieved with the use of the then available vertical cantilever type cats whisker holders, providing stable connections to the central junction and input and output points. The words 'emitter', 'base', 'collector' hadn't yet been born for this new device, which, of course, was destined to become known today as a "transistor".

Inspired by and my experience building a, I've begun experimenting with carborundum to create my own point-contact transistor. As I'm some readers out there have more experience in the field of crystal detectors and similar, I'd love to hear of any experiences/opinions regarding DIY transistors in general - be sure to share any you may have in the comments below.

Flashback: Solar xylophone(02)

With spring in full swing and the sun shining longer every day, we've got solar on the mind. A great summertime project is a flashback from: the Solar Xylophone! How does it work? A regular xylophone fits inside a solar-powered player box that holds a mallet over each of its 8 chime tubes. Each mallet is powered by a system that includes a solar cell, a simple Solarengine circuit, and a small motor. The systems work in parallel: the brighter the sunshine on each panel, the more frequently its corresponding tube will be struck

Now you can listen to sol music by day and be lulled to sleep by the gentle sound of your hard drive wind chime (also in Volume 12) at night:

Here's the for you to scope and build. And for plenty more where that came from, pick up a hard copy of.

Flashback: Solar xylophone (01)