Although the ubiquitous LM386 IC was designed to be used as an audio amplifier, it has a number of undocumented characteristics that can be exploited to create simple radio receiver circuits that ...

VARIABLE condensers are now so commonly employed in radio receivers to tune circuits including a constant inductance that the use, some years ago, of variable inductances or variometers with fixed ...

A tuned circuit formed by a capacitor and an inductor is a familiar enough circuit, and it’s understood that it will resonate at a particular frequency. As that frequency increases, so the size of the ...

Superheterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies ...

Varactor (or “varicap”) diodes are used primarily in radio-frequency (RF) circuits to provide a capacitance that can be varied by changing the applied voltage. These types of diodes often are used for ...

Noel Maginnity is a consultant in Carterton, New Zealand. An alternative audio program input is often required at a medium-wave transmission site. During STL maintenance or if the STL fails, it is ...