This circuit was taken from Maxim documentation from the 1990s. It can be implemented on the basis of modern operational amplifiers. Power supply doesn't have to be symmetrical.
This circuit was found in a former Popular Electronics. The timing is set on the potentiometer and the...
This circuit transmits signals to an FM receiver at a distance of up to a few tens of meters. The...
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...