This circuit is from an Electronics World of 1967. The described calculations can be applied to equivalent circuits with modern transistors.
LTC7841 PolyPhase® Synchronized Boost Controllers Mouser Announces Analog Devices LTC7841...
Found in a Popular Electronics from 1992, this circuit uses a PLL567 in an audio meter bridge that...
This simple musical instrument was obtained from a 1967 magazine. If the original transistors are...