Historic Transistor Photo Gallery

Photo Essay – Shockley 4 Layer Diodes





Schematic of a Unique Shockley Diode Application – An Audio Power Amplifier


Photo Essay Commentary

The above hand-drawn schematic was provided by Ludwell Sibley, with the comment that this had been hurriedly copied from a Shockley Applications sheet years ago.  This audio amplifier is clearly a most unusual application for the Shockley diode, which originally was developed and sold as a switching device.  In fact, it seems that William Shockley was pleased with this use of his invention, and made at least one professional presentation in 1961 to an engineering group about the circuit [4]. 


Ludwell Sibley also relates another unusual application for the Shockley diode: “I don’t know if I should admit this, but in college my dorm roommate was enamored of listening to the theme song from a network show that aired at 11PM nightly.  This included nights before my early-morning ROTC drill.  Fortunately the radio signal was weak. A PNPN diode and 820-pF capacitor, wired in series inside an AC plug, provided effective jamming action: 60 times a second the diode would fire and send a pulse into the capacitor. The effect was indistinguishable from loud fluorescent light noise.”


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