Although it uses a dual-channel FET, which is hard to find today, this circuit was released in a Radio Electronics issue in April 1986. It serves as a signal booster for a wide range of frequencies.
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...
This blocking oscillator was found in a publication from the 50's. The coils determine the...
The TPA3100D2 integrated circuit from Texas Instruments (www.ti.com) consists of an efficient...