This circuit was obtained in a QST magazine from the 90s. The circuit makes use of components that are uncommon today. The circuit includes a gain selection switch.
This circuit is a kind of Hertz Loop that can be used to check the operation of transmitters and...
This high-impedance headphone circuit was found in a 1990s William Sheets. The power is low, but...
Based on the 555, this circuit was obtained from Internet documentation, serving to generate a...