Found in an old American publication, this circuit generates signals of various waveforms. The frequency depends on the components. Operational amplifiers are from the period.
In the figure below we have the way to connect solar cells in parallel to charge a battery in an...
This circuit using 2N2904 general purpose transistors is from a December 1993 Electronics Now...
The purpose of this circuit is to improve the dynamic range of ambient sound systems, preventing them...