This traditional configuration found in a Radio Shack document can use 2N2646. More keys can be added, and the power can be supplied with voltages from 9 to 15 V.
This circuit is from a 1970 publication. The time constant is given by 1.3R x C where R is the...
This oscillator can generate signals up to a few megahertz depending on the crystal used. Actually...
This circuit was obtained from a Popular Electronics of 1994. The magazine no longer exists in its...