We found this configuration in a 70s American documentation. The circuit makes use of operational amplifiers of the time. Modern equivalents can be tested.
This LED effects circuit was found in a 1998 publication, but it can still be easily assembled by the...
This circuit for the 11-meter band, operating at 29.255 MHz was found in a Radio Electronics dated...
Found in na 1969 Electronics World, this circuit makes use of transistors of the time. Equivalent...