• Another strategy for addressing the problem of secondary electrons being attracted by the screen was the addition of a fifth wire element to the tube structure: a suppressor. These five-element tubes were naturally called pentodes.   The suppressor was another…

  • In the beam power tube, the basic four-element structure of the tetrode was maintained, but the grid and screen wires were carefully arranged along with a pair of auxiliary plates to create an interesting effect: focused beams or “sheets” of…

  • As the name suggests, the tetrode tube contains four elements: cathode (with the implicit filament, or “heater”), grid, plate, and a new element called the screen. Similar in construction to the grid, the screen was a wire mesh or coil…

  • De Forest’s Audion tube came to be known as the triode tube because it had three elements: filament, grid, and plate (just as the “di” in the name diode refers to two elements: filament, and plate). Later developments in diode…

  • Thomas Edison, that prolific American inventor, is often credited with the invention of the incandescent lamp. More accurately, it could be said that Edison was the man who perfected the incandescent lamp. Edison’s successful design of 1879 was actually preceded…

  • An often neglected area of study in modern electronics is that of tubes, more precisely known as vacuum tubes or electron tubes. Almost completely overshadowed by semiconductor, or “solid-state” components in most modern applications, tube technology once dominated electronic circuit…

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  • Figure below shows a photodiode amplifier for measuring low levels of light. Best sensitivity and bandwidth are obtained with a trans-impedance amplifier, a current to voltage amplifier, instead of a conventional operational amplifier. The photodiode remains to reverse biased for…

  • When someone mentions the word “computer,” a digital device is what usually comes to mind. Digital circuits represent numerical quantities in binary format: patterns of 1’s and 0’s represented by a multitude of transistor circuits operating in saturated or cutoff…

  • (a) Crystal radio. (b) Modulated RF at antenna. (c) Rectified RF at diode cathode, without C2 filter capacitor. (d) Demodulated audio to headphones.   An antenna ground system, tank circuit, peak detector, and headphones are the main components of a…

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  • Phase shift oscillator. R1C1, R2C2, and R3C3 each provide 60° of phase shift.   The phase shift oscillator of the figure above produces a sine wave output in the audio frequency range. Resistive feedback from the collector would be negative…

  • Note, Q3 and Q4 in the figure below are complementary, NPN and PNP respectively. This circuit works well for moderate power audio amplifiers. For an explanation of this circuit see “Directly coupled complementary-pair,”  Ch 4. Direct coupled complementary symmetry 3…

  • There are three major kinds of power supplies: unregulated (also called brute force), linear regulated, and switching. The fourth type of power supply circuit called the ripple-regulated, is a hybrid between the “brute force” and “switching” designs, and merits a…

  • At the start of this book, we discussed static electricity and how it is created. This has a lot more significance than might be first assumed, as the control of static electricity plays a large part in modern electronics and…

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