This circuit was found in a1980s Motorola documentation. The integrated circuit is from that time. The frequency depends on the crystal.
This circuit was found in old documentation, but the transistor may be the modern equivalent BC547....
Found in Radio Electronics magazine from June 1968, this circuit produces signals from 30 Hz to...
Found in an Australian documentation from 1991, this circuit was sold in a kit at the time. It is a...