Old radios often had selenium rectifiers to convert AC to DC. The problem is that the old units, dating back to 1933, are prone to failure and to release dangerous chemicals like hydrogen selenide. [M ...

The Braun TS2 radio was a state-of-the art tube set in 1956. Today it still looks great, but unsurprisingly, the one that [Manuel Caldeier] has needed a little tender loving care. The table radio had ...

It is shown how the image force can be taken into account very simply by making a minor improvement in the current theory of rectification. The equations obtained have been compared with experimental ...