This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
A modulated (flashing) siren using the four gates of the 4001 integrated is shown in the figure....
May 2017 - Mouser Electronics already has Microchip's new MCP14A0451 and MCP14A0452 integrated...
Mouser Electronics has in stock Texas Instruments Buck controllers LM5145 to operate with voltage...