Found in a Popular Electronics from the 90's, this circuit can generate frequencies according to the values of the employed components, according to the table next to the diagram.
This circuit was obtained in an 1975 English publication. It is a voltage regulator circuit for...
In the figure we have an infrared receiver circuit using an operational 741. The circuit is an...
This circuit is suggested by National Semiconductor and makes use of the negative regulator LM2990...