This integrating circuit multiplies the time that can be obtained with a 555 timer. We find it in an Electronic Design from the 90s. The circuit uses components that are still common today.
This circuit appears in several configurations in this site. This is from American documentation from...
Using two LM377s, this amplifier provides a few watts of audio in a low impedance speaker and the power...
Found in a 1969 EEE, this circuit converts input pulses into linear sawtooth signals, as shown in...