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This variable frequency oscillator was found in an old American documentation. Transistors allow more modern equivalents and coil data are found next to the diagram for several frequency bands.
Found in a 90s EDN, this circuit is indicated for power control through a 4-20 mA line. The...
In the figure we have an improved method of varying the voltage of a 7812 regulator. The circuit is...
This circuit was found in an Electronic Engineering of the 80s. The circuit indicates when a...