This well-known circuit version of the siren was obtained in a Colectro Handbook from the 70s. The transistors are of general use, with Q2 being a BD136 for greater power with power from 6 to 12 V.
Although the BD135 transistor is not specifically for RF applications, some of them can easily...
This transmitter for modulated radiation can be used as an optical data shield. The maximum...
This ultra-low noise circuit was found in the May 1990 issue of Radio Electronics magazine. The...