This audio oscillator is from a 1957 Raytheon publication. The tone generated depends on C2 and C2 and the handset must be high-impedance magnetic. Equivalent transistors can be tested.
Using the ICM7556, dual CMOS version of the 555, this circuit generates triangular signals from 1 to...
We found this circuit in an English magazine from 1976. The magazine no longer exists, but just...
This circuit was obtained from an English magazine from 1977. The magazine no longer exists, but...