80 Candles for the Pentode

The first transistor radio was called Regency TR-1 and appeared on the market in 1954, at a time when radios with vacuum tubes had been around for decades. One of the most successful tubes is the pentode, a vacuum electron tube with five (Greek: pente) electrodes. A famous early pentode was the ‘RCA-34’ (UX-234), it reached commercial use in the early 1930s and was announced as a ‘Super-Control R-F Amplifier Pentode’.