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 filter, from an audio publication from 1977, passes the frequency range corresponding to the...
In the figure we have three voltage doubler configurations that can be used in high and low...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...