This circuit, suggested by an Electronics World of 1969, keeps a blinking LED for a while when a power outage occurs. Time depends on capacitor C1.
We found this circuit in a 1977 Radio Handbook. The JFET can be of any type and the adj can have...
This pulse integrator was found in Radio Electronics magazine from November 1960. The components are...
We found this circuit in a publication from the 1970s. The circuit has a logarithmic gain...