Found in the February 1983 Radio Electronics magazine, this circuit uses a FET and has good gain at the frequencies determined by the components. The FET is any general-purpose FET.
Found in a Popular Electronics from the 1990s, this circuit uses components from National...
This combination key or code key was found in old documentation. The consumption is very low, and...
This circuit was found in a European documentation from 1964. The circuit makes use of components of...