It had been only a little over a decade since the transistor was invented when this article appeared in the August 1959 edition of Popular Electronics. Transistors were still a mystery to most people, including engineers, technicians, and hobbyists. Author James Butterfield takes a unique approach in presenting the material by writing it as a dialog between an instructor and a student.
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If you are also new to transistors, this will be worth your while to read. Pete introduces Johnny to the grounded emitter circuit. Its "why`s" and "how`s" are investigated and the not-too-mysterious matters of base and collector bias are discussed. The rule is, as Pete explains it, "Let Ohm`s Law be your guide. " Trying to design a one-transistor amplifier, Johnny gets tangled up with input and output impedance problems. Pete straightens him out with some important "do`s" and "don`ts" in getting a signal in and out of a transistor. The transistorized approach to filters and tone and volume controls is detailed by Pete with some practical suggestions on the testing of transistor characteristics. Coupling problems are discussed, and Pete draws up a chart that matches the coupling capacitor to the collector resistor "That`s an amplifier " snorted Johnny. "You must have dreamed up that circuit during a fit of indigestion! Anybody knows even the simplest transistor amplifiers are bristling with resistors and oversize coupling capacitors. And where`s the output transformer for the speaker " "Don`t need any. " Pete clipped on the ground lead from the audio generator and inserted a. 1- µf. capacitor in series with the other lead. "Trouble with most of you experimenters is that you just copy diagrams - maybe change `em a little here and there to see what happens - but you never bother to find out what really makes things tick. " He...
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The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
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The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
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In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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