![1. For the following circuit, assume the values of the resistor R is 1](http://s1.studyres.com/store/data/006670177_1-f79d6bf159f68da59de146ccd3e2b579-300x300.png)
Transformers
... A step-up transformer has more turns on the secondary coil and so increases voltage. 3 of 6 ...
... A step-up transformer has more turns on the secondary coil and so increases voltage. 3 of 6 ...
Lec 04
... series resonant circuit with a given resistance, the higher the inductance and the lower the capacitance, the narrower the filter bandwidth. For a parallel resonant circuit, the opposite applies. At resonant frequency: series = short; parallel = open. ...
... series resonant circuit with a given resistance, the higher the inductance and the lower the capacitance, the narrower the filter bandwidth. For a parallel resonant circuit, the opposite applies. At resonant frequency: series = short; parallel = open. ...
Single Transistor Crystal Oscillator Circuits
... this point is loaded so as not to reflect back into the oscillator loop and adversely affect the oscillators performance. The waveform on the transistor emitter is not sinusoidal but rather a small rounded ‘square wave’ of typically 0.3V / 1V pk/pk and 15% / 30% duty cycle. This is because the circu ...
... this point is loaded so as not to reflect back into the oscillator loop and adversely affect the oscillators performance. The waveform on the transistor emitter is not sinusoidal but rather a small rounded ‘square wave’ of typically 0.3V / 1V pk/pk and 15% / 30% duty cycle. This is because the circu ...
Wireless power for mobile phones
... Figure 1: http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/ Figure 2: http://makezine.com/2013/11/04/component-of-the-monthtransformer/ Figure 3: http://www.britannica.com/EBchecked/media/1355/Magnetic-field-B-of-two-current-loops-with-currents-in ...
... Figure 1: http://www.electrical4u.com/what-is-transformer-definition-working-principle-of-transformer/ Figure 2: http://makezine.com/2013/11/04/component-of-the-monthtransformer/ Figure 3: http://www.britannica.com/EBchecked/media/1355/Magnetic-field-B-of-two-current-loops-with-currents-in ...
examination of marine engineer officer
... load current is 3A at 0.2 power factor lag when the secondary current is 280A at a power factor of 0.8 lagging. Assume the voltage drop in the winding to be negligible. Find the current taken by the primary and its power factor. 2. A wooden ring has a mean diameter of 20 cm and a cross-sectional are ...
... load current is 3A at 0.2 power factor lag when the secondary current is 280A at a power factor of 0.8 lagging. Assume the voltage drop in the winding to be negligible. Find the current taken by the primary and its power factor. 2. A wooden ring has a mean diameter of 20 cm and a cross-sectional are ...
LEP 4.4.04 Coil in the AC circuit
... value. The frequency is varied until there is the same voltage drop across the coil as across the resistor. The resitance and impedance values are then equal: ...
... value. The frequency is varied until there is the same voltage drop across the coil as across the resistor. The resitance and impedance values are then equal: ...
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.