Chapter 3 Special
... of the voltage across the element is determined by the opposition of the element to the flow of charge, or current i. For a resistive element, we have found that the opposition is its resistance and that velement and i are determined by velement = iR. The inductance voltage is directly related to th ...
... of the voltage across the element is determined by the opposition of the element to the flow of charge, or current i. For a resistive element, we have found that the opposition is its resistance and that velement and i are determined by velement = iR. The inductance voltage is directly related to th ...
3 System definition - Telecommunications Industry Association
... TIA/EIA-485-A, referred to as 485 hereafter, to form a balanced multipoint data bus. The versatility of the 485 electrical standard covers a wide variety of data interchange applications all of which this publication cannot cover. The intent is to provide basic design guidelines of the physical laye ...
... TIA/EIA-485-A, referred to as 485 hereafter, to form a balanced multipoint data bus. The versatility of the 485 electrical standard covers a wide variety of data interchange applications all of which this publication cannot cover. The intent is to provide basic design guidelines of the physical laye ...
here - NOGA QRP Club
... time determined by the setting of R4. In actual use, set the delay so that the relay will stay energized during normal pauses in sending CW, just like you would adjust the VOX on a transmitter. Congratulations you now have a working NoGa Guppy! You will need to decide how to connect the “mute; NO; N ...
... time determined by the setting of R4. In actual use, set the delay so that the relay will stay energized during normal pauses in sending CW, just like you would adjust the VOX on a transmitter. Congratulations you now have a working NoGa Guppy! You will need to decide how to connect the “mute; NO; N ...
Diode - WordPress.com
... Electricity uses up a little energy pushing its way through the diode, rather like a person pushing through a door with a spring. This means that there is a small voltage across a conducting diode, it is called the forward voltage drop ...
... Electricity uses up a little energy pushing its way through the diode, rather like a person pushing through a door with a spring. This means that there is a small voltage across a conducting diode, it is called the forward voltage drop ...
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.