The frequency of this circuit depends on C1 and, for the indicated values, it is 1 kHz. Equivalent operational amplifiers can be used, and the power supply must be symmetrical.
This circuit appears elsewhere on this site using the most diverse transistors. This version is...
Frequency in this oscillator is controlled by a crystal. Any 1 MHz to 15 MHz can be used. The JFET can...
This was one of the National Semiconductor clock modules very popular in the 70s and 80s. In the...