This circuit was taken from old American documentation. The transistors used make it possible to control a motor with up to 2 A of current. They must be equipped with heat sinks.
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The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...