This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
This circuit was found in the March 1995 issue of Electronics Now magazine. The circuit requires a...
This receiver was found in a documentation by Gernsback from 1960. The circuit uses high impedance...