Designed for the audio track, this circuit was found in a Popular Electronics from the 90's. Other operational can be used and R7 can be 470 k. The frequency is 1 kHz.
This circuit was found in a British documentation from 1969. It can be implemented with modern...
A simple VCO using two inverters in a ring configuration is shown here. A VCO is a circuit in...
The four gates of a 40111 IC are used in thes two-out circuit. The output chages their state in a...