This circuit mimics the trill of a bird. We found it in an American documentation from the 90s. It is based on the LM3909 integrated circuits.
This sensitive touch key appears on this website from other sources. This version was taken from a...
This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used...
CMOS 4046 (PLL) is not very common. In this circuit it generates short pulses to excite a high...