We found this circuit in a publication from the 1980s. Transistors can be replaced by current equivalents. The circuit is for 6 V and the capacitors determine the frequency of the oscillations.
This circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The circuit presented generates short pulses. This configuration was found in a publication from...