Schematic Symbols - CTE-Auto
... repeatedly changed mechanically or electronically. Variable capacitors are often used in L/C circuits (tuners) to set the resonance frequency, e.g. to tune a radio (therefore they are sometimes called tuning capacitors) ...
... repeatedly changed mechanically or electronically. Variable capacitors are often used in L/C circuits (tuners) to set the resonance frequency, e.g. to tune a radio (therefore they are sometimes called tuning capacitors) ...
Technician Study Sheet Instructions
... Good Amateur Practices The radio spectrum is a shared resource and the FCC rules are largely based on “play nicely with others”. Good Amateur Practice is exactly that. They include “listen before transmitting” to insure the frequency isn’t already being used. If you want to break into a conversation ...
... Good Amateur Practices The radio spectrum is a shared resource and the FCC rules are largely based on “play nicely with others”. Good Amateur Practice is exactly that. They include “listen before transmitting” to insure the frequency isn’t already being used. If you want to break into a conversation ...
HERO Jr POWER SUPPLY PROTECTION
... The antenna signal passes via Transformer 1 (TR1) into one gate of the dual gate fet and the local oscillator is injected into the other gate. The Fet acts a non linear amplifier and signal mixer. As a result the sum & difference of the received signal and local oscillator signal appear in the Fet’s ...
... The antenna signal passes via Transformer 1 (TR1) into one gate of the dual gate fet and the local oscillator is injected into the other gate. The Fet acts a non linear amplifier and signal mixer. As a result the sum & difference of the received signal and local oscillator signal appear in the Fet’s ...
Name: Magnetic Materials – Practice 1. In an oscillating LC circuit
... Magnetic Materials – Practice 1. In an oscillating LC circuit with L = 50 mH and C = 4.0 μF, the current is initially a maximum. How long will it take before the capacitor is fully charged for the first time? ...
... Magnetic Materials – Practice 1. In an oscillating LC circuit with L = 50 mH and C = 4.0 μF, the current is initially a maximum. How long will it take before the capacitor is fully charged for the first time? ...
The Colpitts Oscillator
... generation of higher frequencies of oscillation. • Because of lower unity gain frequency of most op amps, discrete transistors are often used as the gain elements in LC Feedback oscillators. • Colpitts, Clapp, Hartley, Armstrong and Crystal controlled oscillators are the examples ...
... generation of higher frequencies of oscillation. • Because of lower unity gain frequency of most op amps, discrete transistors are often used as the gain elements in LC Feedback oscillators. • Colpitts, Clapp, Hartley, Armstrong and Crystal controlled oscillators are the examples ...
Crystal radio
A crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no other power source but that received solely from the power of radio waves received by a wire antenna. It gets its name from its most important component, known as a crystal detector, originally made from a piece of crystalline mineral such as galena. This component is now called a diode.Crystal radios are the simplest type of radio receiver and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of copper wire for adjustment, a capacitor, a crystal detector, and earphones. They are distinct from ordinary radios as they are passive receivers, while other radios use a separate source of electric power such as a battery or the mains power to amplify the weak radio signal so as to make it louder. Thus, crystal sets produce rather weak sound and must be listened to with sensitive earphones, and can only receive stations within a limited range.The rectifying property of crystals was discovered in 1874 by Karl Ferdinand Braun, and crystal detectors were developed and applied to radio receivers in 1904 by Jagadish Chandra Bose, G. W. Pickard and others.Crystal radios were the first widely used type of radio receiver, and the main type used during the wireless telegraphy era. Sold and homemade by the millions, the inexpensive and reliable crystal radio was a major driving force in the introduction of radio to the public, contributing to the development of radio as an entertainment medium around 1920.After about 1920, crystal sets were superseded by the first amplifying receivers, which used vacuum tubes (Audions), and became obsolete for commercial use. They, however, continued to be built by hobbyists, youth groups, and the Boy Scouts as a way of learning about the technology of radio. Today they are still sold as educational devices, and there are groups of enthusiasts devoted to their construction who hold competitions comparing the performance of their home-built designs.Crystal radios receive amplitude modulated (AM) signals, and can be designed to receive almost any radio frequency band, but most receive the AM broadcast band. A few receive shortwave bands, but strong signals are required. The first crystal sets received wireless telegraphy signals broadcast by spark-gap transmitters at frequencies as low as 20 kHz.