This sound effect circuit is from a Radio Electronics magazine from December 1969. The transistors support equivalents and the power is provided by a battery to reduce the possibility of noise.
This low frequency circuit was found in documentation from the 1980s. The values of R and C...
This source for devices for automotive use was found in a 1985 documentation. The power...
Found on Popular Electronics in the 1980s, this circuit detects a change in air pressure using a...