This circuit was found in documentation from the 1970s. The transistor supports modern equivalents. L1 with C4 determines the frequency range of the signals that will be produced.
This circuit matches a source of high or medium impedance audio signals with a low impedance...
Found in a 1993 Electronics Hobbyst Handbook, this circuit uses components that are still common...
This pulse width-tuned circuit was found in the March 1996 issue of Electronics Now magazine. The...