The fundamentals of crystals has not changed since this article appeared in a 1960 edition of Popular Electronics. The way they are grown, cut, and packaged has changed fairly significantly. An understanding of how they work at the atomic level has advanced significantly. The number of devices in which they are contained has increased significantly.
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However, except for the vacuum tubes in these oscillator circuits being replaced by transistors, nothing much has changed. An amateur radio operator, an airline pilot, a police radio dispatcher, a broadcast-station announcer. sound like a hodge-podge of job holders Maybe so, but they have at least one thing in common. All make daily use of the peculiar properties of quartz crystals - thin, glass-like plates that keep the world in tune. Crystals are found in almost all commercial and ham radio equipment, but few of their users know how they work. Before we examine the details of crystal operation, let`s take time out to define our terms. There are three important words involved: resonance, damping, and piezoelectricity. Fig. 1. In a typical oscillator circuit, turning the oscillator on develops a voltage between its cathode and grid, and this voltage shocks the crystal into vibration at its resonant frequency. The vibration in turn develops an alternating voltage across the crystal terminals, which is amplified by the tube. The LC circuit is tuned near the crystal frequency and presents a high impedance in the tube`s plate circuit. Consequently, a portion of the amplified voltage is fed back to the crystal and maintains oscillation. Fig. 4. Overtone oscillator will provide output up to 60 mc. with crystals ground for third-harmonic operation. LC circuit must be tuned to output frequency. Structurally, the piezoelectric...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
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....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
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....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
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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