We found this circuit in a 1980s American documentation. The operational amplifiers of the integrated circuit used can be common types in an experimental setup.
For the 7 to 10 MHz band L1 is formed by 3 turns of 22 to 28 AWG wire in a ferrite core 15 to 20...
We found this interesting timer circuit or CMOS timer in a 1988 publication. The circuit is still...
This audio mixer was found in an old American documentation. The potentiometers are 1M and the...