The circuit below is suggested by National Semiconductor in technical documentation on the LM3909. The circuit is powered by a single battery and has a very low consumption.
This circuit is valid for 106 series SCRs and can be modified to operate on the 110V power grid....
Found in an October 1992 Radio Electronics magazine article, this circuit generates a low-power tone in...
This circuit was obtained in a Popular Electronics of the 90s. The circuit is compatible with...