Converting ac to dc has been accomplished by several different types of rectifiers through the years. Here are a few of the more common types of rectifiers used in the past 100 years. Mercury arc ...

An 8-pin base with center post, metal shell, and glass insulator. T-shaped envelope. Stamped: "35Z3". Philco stamp on envelope under masking tape. Donor’s card reads: “Half wave high vacuum rectifier ...

Older table-top AC-DC radios used a classic line-up of tubes. Think 12SA7, 12SK7,12SQ7, 35Z5GT, and 50L6GT. As I grew into my teens, I got interested in how these radios worked and soon discovered ...

WHEN an alternating current arc is established in a vacuum tube between a mercury and an iron or graphite electrode, the current only passes during half the time, namely, when the mercury pool is the ...

A 4-pin brass base with ceramic insulator, two parallel elements mounted vertically, tipless S-shaped envelope. Printing on base mostly indistinct: "U ...