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First Oscillators Sheet
... In either case, when the j terms have vanished, V 2/V1 = XR/(3XR) = 1/3, so the amp. needs a gain of 3 at least. This means R1 > 3R2. A problem is that if the gain is less than 3 the circuit does not oscillate, but if the gain is even slightly greater than 3 a non-sinusoidal output results because t ...
... In either case, when the j terms have vanished, V 2/V1 = XR/(3XR) = 1/3, so the amp. needs a gain of 3 at least. This means R1 > 3R2. A problem is that if the gain is less than 3 the circuit does not oscillate, but if the gain is even slightly greater than 3 a non-sinusoidal output results because t ...
Operating DC Relays from AC and vice
... To develop the required power, coil voltage would have to be increased to that value where sufficient current flows. In theory, then, AC can be used to operate a DC relay. In reality, however, doing so is impractical. Since alternating current decreases to zero every half-cycle (120 times per second ...
... To develop the required power, coil voltage would have to be increased to that value where sufficient current flows. In theory, then, AC can be used to operate a DC relay. In reality, however, doing so is impractical. Since alternating current decreases to zero every half-cycle (120 times per second ...
Notes of key concepts_Ch8
... The circuit breaker It automatically ‘switches off’ if the current in a circuit exceeds its rating. We can reset the circuit breaker by switching it back on. ...
... The circuit breaker It automatically ‘switches off’ if the current in a circuit exceeds its rating. We can reset the circuit breaker by switching it back on. ...
for Coil Detuning - Efficient Power Conversion
... L saline phantom (2.4 g/L NaCl, 1.0 g/L CuSO4), with the coil impedance matched to 50 Ω (S11<-45 dB). When using the eGaN FET switch, an external circuit was used to convert the normal bias Figure 3: Photograph of the eGaN detuning circuit signal from the scanner into a 0-5V logic signal. Results: T ...
... L saline phantom (2.4 g/L NaCl, 1.0 g/L CuSO4), with the coil impedance matched to 50 Ω (S11<-45 dB). When using the eGaN FET switch, an external circuit was used to convert the normal bias Figure 3: Photograph of the eGaN detuning circuit signal from the scanner into a 0-5V logic signal. Results: T ...
Negative capacitance effect in semiconductor devices - DR-NTU
... very suitable to describe the inductive device behavior. However, most of the semiconductor devices have positive capacitance, and the term “NC” was introduced to describe a very rare, unusual situations when imaginary part of admittance is negative [for convention I; V exp(i!t)]. It should be p ...
... very suitable to describe the inductive device behavior. However, most of the semiconductor devices have positive capacitance, and the term “NC” was introduced to describe a very rare, unusual situations when imaginary part of admittance is negative [for convention I; V exp(i!t)]. It should be p ...
Ohms Law and Circuits WKSHT
... a. Draw the circuit diagram. b. What is the total resistance of the load? c. What is the magnitude of the circuit current? 16. The load across a 40-V battery consists of a series combination of three resistances R1, R2, and R3. R1 is 240 3 is 120 . The potential difference across R1 is 24 V. a. ...
... a. Draw the circuit diagram. b. What is the total resistance of the load? c. What is the magnitude of the circuit current? 16. The load across a 40-V battery consists of a series combination of three resistances R1, R2, and R3. R1 is 240 3 is 120 . The potential difference across R1 is 24 V. a. ...
Circuit Components Lesson 4
... resistance for the circuit. This allows the current to be determined easily. The current flowing through each resistor can then be found by undoing the reduction process. Two (or more) resistors with their heads directly connected together and their tails directly connected together are in parallel ...
... resistance for the circuit. This allows the current to be determined easily. The current flowing through each resistor can then be found by undoing the reduction process. Two (or more) resistors with their heads directly connected together and their tails directly connected together are in parallel ...
Slide 1
... Kirchoff: q/C1 + iR + q/C2 + ir = q(1/C1 + 1/C2) + i (R+r) = Compare with what we had for the simple RC circuit Here we had Kirchoff: iR + q/C = Thus, our circuit is equivalent to a simple RC circuit with series resistance (r+R) and capacitors C1 26 and C2 in series! ...
... Kirchoff: q/C1 + iR + q/C2 + ir = q(1/C1 + 1/C2) + i (R+r) = Compare with what we had for the simple RC circuit Here we had Kirchoff: iR + q/C = Thus, our circuit is equivalent to a simple RC circuit with series resistance (r+R) and capacitors C1 26 and C2 in series! ...
Document
... inductance does not depend upon the radius of the wire itself and increasing this radius decreases the resistance, I could easily create another coil of similar inductance and less resistance by winding a thicker wire (with greater radius and lower resistance) of the same material around the same co ...
... inductance does not depend upon the radius of the wire itself and increasing this radius decreases the resistance, I could easily create another coil of similar inductance and less resistance by winding a thicker wire (with greater radius and lower resistance) of the same material around the same co ...
Analysis of Low Pass Filter and Voltage Dividers
... design parameters as SPICE, but for completeness, simulations were run in both. It was not too time consuming to do both, as the programs are generally easy to work with. The transient analysis w ...
... design parameters as SPICE, but for completeness, simulations were run in both. It was not too time consuming to do both, as the programs are generally easy to work with. The transient analysis w ...
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.