The low-noise amplifier shown uses a rare Raytheon operational amplifier today. The circuit can be implemented with more modern operators and the power source must be symmetrical.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...