This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The components used are common and the timing is given by the capacitor C1 which can be changed.
This circuit uses the first commercial Darlington transistor, the 2N626. We found it in Radio...
This antenna amplifier or booster for receivers from 100 kHz to 30 MHz was published in a...
This simple CMOS metronome circuit can be mounted in a small box, providing both sound and light...