Antenna Theory - The Free Information Society
... negative terminal as far as possible while the positive terminal will attract electrons. View B of Figure 1-1 shows the direction and distribution of electron flow. The distribution curve shows that most current flows in the center and none flows at the ends. The current distribution over the antenn ...
... negative terminal as far as possible while the positive terminal will attract electrons. View B of Figure 1-1 shows the direction and distribution of electron flow. The distribution curve shows that most current flows in the center and none flows at the ends. The current distribution over the antenn ...
Speaker motors and passive crossover filters
... devices are reactive in nature. They are usually primarily resistive, but are just as often highly inductive and sometimes primarily inductive. And whether or not a motor has more inductive reactance or resistance, it will always exhibit a mechanical resonant frequency, which causes it to act as tho ...
... devices are reactive in nature. They are usually primarily resistive, but are just as often highly inductive and sometimes primarily inductive. And whether or not a motor has more inductive reactance or resistance, it will always exhibit a mechanical resonant frequency, which causes it to act as tho ...
SPH3U1: ELECTRICITY AND MAGNETISM TEST Answer Section
... b. 800-W toaster e. none of the above c. 1000-W hair dryer ____ 18. Three 10.0-resistors are connected in parallel to one another in a 12.0-A circuit. The total resistance in the circuit is a. 0.0333 d. 20.0 b. 0.300 e. 30.0 c. 3.33 ____ 19. An electric toaster draws 5.00 A from a 120-V ...
... b. 800-W toaster e. none of the above c. 1000-W hair dryer ____ 18. Three 10.0-resistors are connected in parallel to one another in a 12.0-A circuit. The total resistance in the circuit is a. 0.0333 d. 20.0 b. 0.300 e. 30.0 c. 3.33 ____ 19. An electric toaster draws 5.00 A from a 120-V ...
Radiometer systems
... Here B is the RF bandwidth and is the integration time (s) constant which is related to the low-pass filter’s bandwidth by BLPF 1/(2 ), Hz. ...
... Here B is the RF bandwidth and is the integration time (s) constant which is related to the low-pass filter’s bandwidth by BLPF 1/(2 ), Hz. ...
32 kHz Oscillator Start-up Time and POR Pulse Width Considerations
... interrupted. The diode may be either a standard silicon diode or Schottky diode, with the latter offering improved performance by discharging the circuit more quickly to a lower voltage. V+ ...
... interrupted. The diode may be either a standard silicon diode or Schottky diode, with the latter offering improved performance by discharging the circuit more quickly to a lower voltage. V+ ...
Eng - unesdoc
... The number of hours stated in the curriculum table may be increased or decreased to suit individual institutions’ timetable provided the entire course content is properly covered and the goals and objectives of each module are achieved at the end of the term. The maximum duration of any module in th ...
... The number of hours stated in the curriculum table may be increased or decreased to suit individual institutions’ timetable provided the entire course content is properly covered and the goals and objectives of each module are achieved at the end of the term. The maximum duration of any module in 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.