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RC time constants
... charges quickly, but then as it gets more and more full of charge the rate it charges at gets less and less. Mathematically speaking the capacitor never quite reaches fully charged, however in practice it gets so close to being fully charged we couldn't tell. ...
... charges quickly, but then as it gets more and more full of charge the rate it charges at gets less and less. Mathematically speaking the capacitor never quite reaches fully charged, however in practice it gets so close to being fully charged we couldn't tell. ...
Lecture 1 (2)
... small signals. In electronic circuits, static signals usually define operating points of electronic devices to provide a required translation (gain) for small signals. Static signals are defined by the designer. The origin of small signals is usually external. They enter the circuit through either a ...
... small signals. In electronic circuits, static signals usually define operating points of electronic devices to provide a required translation (gain) for small signals. Static signals are defined by the designer. The origin of small signals is usually external. They enter the circuit through either a ...
doorbell extender
... must not be overlooked that both the Transmitter and Receiver need links to the mains supply and all the usual precautions MUST be taken in making up and testing these circuits. The Transmitter circuit is built on a small printed circuit board (p.c.b.). The topside component layout and full-size und ...
... must not be overlooked that both the Transmitter and Receiver need links to the mains supply and all the usual precautions MUST be taken in making up and testing these circuits. The Transmitter circuit is built on a small printed circuit board (p.c.b.). The topside component layout and full-size und ...
Document
... levels of the steady state output signal from RC high pass circuit is always zero 2. (a) Write a short notes on RC low pass circuit (b) Draw the output response of RC low pass circuit for a step input signal and explain in detailed. c)Explain how a low pass RC circuit act as an integrator. 3. (a) Ex ...
... levels of the steady state output signal from RC high pass circuit is always zero 2. (a) Write a short notes on RC low pass circuit (b) Draw the output response of RC low pass circuit for a step input signal and explain in detailed. c)Explain how a low pass RC circuit act as an integrator. 3. (a) Ex ...
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.