Helium-filled full-wave rectifier. A 4-pin base with brass shell and ceramic insulator. Tipped S-shaped envelope. Serial number "5144". Two ceramic-covered cylinders are set side by side on top the ...

A plastic 4-pin base with S-shaped envelope, getter stain, two mesh-type vertical elements, one mounted on either side of stem. Stamped on base: "1207". One label reads: "Concert / Master"; another ...

A classic analog application is the precision active full-wave rectifier. Many different implementations exist of this theme, each with its own supposed advantages. However, one circuit element needed ...