This circuit was found in old American documentation. It is a Wien bridge with the component values calculated by the formulas next to the diagram.
This relay shield was found in the October 1993 Electronics Now magazine. The circuit is powered by...
In the figure we have the basic configuration of a regulator for 12 V x 1 A suggested by Motorola in...
This circuit can be used as part of a Vox project or as an input shield for a microcontroller that...