This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This circuit was found in the October 1994 issue of Electronics Now magazine. The 40446 IC is a...
Found in a 1967 EEE, this circuit generates a constant amplitude signal, stabilized by a zener...
This circuit is from the November 1974 issue of Radio Electronics magazine. The capacitor...