This interference rejection circuit for telegraphy was found in a 1980s documentation for radio amateurs. The integrated circuits used are common today.
This circuit generates pulses at a frequency that can be adjusted by a potentiometer. The circuit is...
This 1.5 A circuit is from the LM117 manual. The LM350 can be used for higher current, and the...
The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. Other...