This simple tone control using two transistors was found in an Electronics Today International of the 90s. Transistors are general purpose NPN types, like the BC549 for greater gain.
This circuit is from the 1983 Intersil Databook. The ADC0801 and 0804 are low-cost AD converters. They...
This circuit uses only two transistors, the first being low noise, being indicated for dynamic...
This circuit divides the frequency of a signal by two. The circuit is found in the May 1977 issue...