The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. Some of the components are not currently common and should be looked for equivalents.
This filter rejects 60 Hz signals and can be used as a hum filter in audio equipment, for example, at...
Taking advantage of the comparator setting, we can use the Norton amplifier as an over temperature...
This simple SCR relaxation oscillator was indicated by a 90s Popular Electronics. The frequency is...