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.
This circuit is from old documentation. The operational amplifier is uncommon nowadays. The...
This memory flip-flop must be powered by 5V voltage. The circuit stores 1 bit. ...
This simple preamplifier was published in Radio Electronics magazine in February 1958. The battery...