This circuit was found in documentation for radio amateurs of the 1980s. This is the so-called roger-beep, which is the beep that is transmitted when the talk-listen function is changed.
The Texas Instruments LM5178 Buck-boost controller is capable of operating in the 4.2 to 55 V (60...
This 1970 Philips circuit uses a mechanical counter. The circuit is triggered by a reed switch...
This 1 MHz oscillator was found in an Electronics World of 1969. The circuit uses a...