This circuit was described in an article in the February 1993 Radio Electronics magazine. The frequency depends on the crystal and L1 is optional.
Found in Unitrode documentation, this oscillator uses some unusual components today such as PU and...
This circuit was obtained from a Popular Electronics of 1994. The magazine no longer exists in its...
We found this circuit in an old English documentation from the 70s. The transistor can be a modern...