This circuit is from a 1968 Electronic Design. The circuit uses transistors of the time that can be replaced with modern equivalents. More stages can be used to get higher tension.
Two operational are used on this triangular-rectangular oscillator suggested by Motorola in its...
This circuit from a Popular Electronics from the 90's can generate signals from 0.03 Hz to 3 kHz...
With 8 to 30 V power supply, the output power depends on both the voltage and the load. The...