Electronics Teach-in Part 6:
Regulators 1 by M. A. Stracey Eng. Tech. (AMIEIE) G7LKJ. With Fig. 1 - 7 diagrams detailing Zenor Diode Regulator Circuits and Diode Characteristics. With 1, 2, or 3 transistor gain using the 'Darlington connection' method.
In-Circuit Transistor Tester by Alan Willcox. Using the obicuous 555 timer, a 4 Diode Bridge... Plus Components List, PCB track layout (for etching your own PCB), component layout, and Test conditions and results table.