![香港考試局](http://s1.studyres.com/store/data/004062950_1-8e529f8faa21638aa17c7882e5b20479-300x300.png)
Lab7Procedure
... Lab # 7 – Signal Conditioning with Op Amps Purpose: The purpose of this lab is study signal conditioning with various op amp configurations. Equipment Required: ...
... Lab # 7 – Signal Conditioning with Op Amps Purpose: The purpose of this lab is study signal conditioning with various op amp configurations. Equipment Required: ...
UNDERSTANDING MICROPHONES - Wodonga Senior Secondary …
... The dynamic microphone uses a wire coil and magnet to create to create the audio signal. The diaphragm is attached to the coil. When the diaphragm vibrates in response to incoming sound waves, the coil moves backwards and forwards past the magnet. This creates a current in the coil which is channele ...
... The dynamic microphone uses a wire coil and magnet to create to create the audio signal. The diaphragm is attached to the coil. When the diaphragm vibrates in response to incoming sound waves, the coil moves backwards and forwards past the magnet. This creates a current in the coil which is channele ...
Advanced Circuits
... Introduction: Have you ever touched an incandescent light bulb that has been on for a while? Ouch! What you feel is frictional heat produced by the current moving through the light’s resistor. The high heat produced in electric circuits leads to the danger of electrical fires. A fuse is a safety dev ...
... Introduction: Have you ever touched an incandescent light bulb that has been on for a while? Ouch! What you feel is frictional heat produced by the current moving through the light’s resistor. The high heat produced in electric circuits leads to the danger of electrical fires. A fuse is a safety dev ...
Transmission Line Theory
... and an electrical length of 0.3λ. The line is terminated with an impedance having a resistive component of 25Ω and an inductive reactance of 25Ω. What is the input impedance to the line? ...
... and an electrical length of 0.3λ. The line is terminated with an impedance having a resistive component of 25Ω and an inductive reactance of 25Ω. What is the input impedance to the line? ...
A SLOTTED LECHER LINE FOR lMPEDANCE - Research
... unbalanced (unsymmetrical) test equipment, special fourpoles or "baluns" being inserted to effect the transition from balance to unbalance. Generally speaking such inserted devices are open to the following objections: either they have a very narrow frequency band and must accordingly be matched wit ...
... unbalanced (unsymmetrical) test equipment, special fourpoles or "baluns" being inserted to effect the transition from balance to unbalance. Generally speaking such inserted devices are open to the following objections: either they have a very narrow frequency band and must accordingly be matched wit ...
Lecture 11 slides - Digilent Learn site
... Thévenin’s Theorem – “Derivation” • Represent circuit “B” (load) as a current source, providing some voltage • Note that we haven’t changed the i-v characteristics at terminals! Circuit iB (Load) ...
... Thévenin’s Theorem – “Derivation” • Represent circuit “B” (load) as a current source, providing some voltage • Note that we haven’t changed the i-v characteristics at terminals! Circuit iB (Load) ...
Technical Information Technical Information
... woofer. A very small air leak anywhere near the woofer can dramatically reduce low frequency output and negatively affect the frequency response of the driver. Additionally, it is very important to securely mount the woofer on a rigid baffle. Any energy that moves or vibrates the baffle is energy th ...
... woofer. A very small air leak anywhere near the woofer can dramatically reduce low frequency output and negatively affect the frequency response of the driver. Additionally, it is very important to securely mount the woofer on a rigid baffle. Any energy that moves or vibrates the baffle is energy th ...
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.