This circuit is from a 90s Popular Electronics. The circuit employs a ZN461E that is not a common component today.
The SN72741 integrated circuit is nothing more than the version of Texas Instruments of the known...
This circuit came out in a 1978 American publication, but can be assembled with transistors BC547 or...
Found in documentation for radio amateurs of the 70's, this circuit generates signals from 18 to 24...