Found in 1969 RCA documentation, this dimmer uses a dual time constant setting to achieve better control of the triac's trigger point.
We found this circuit in a 1965 Electronic Design. The transistors are from the era, and modern...
This preamplifier is indicated for low and high-impedance sources as microphones, transducers,...
Found with variations on this site, this circuit was taken from an American documentation from the...