lompa said:
all the basic ones, resistance, charge, power, capacitance, transistor gain, inductance, impedance ect
Thanks
Okay, that gives us something to go on.
* Resistance (R) is given by doing some manipulation of 0hm's Law. Since V= I*R, dividing both sides of the equation by "I" yeilds R = V/I.
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* Impedance (Z) is a combination of resistance (a real number) and reactance (an imaginary). Given that, you can expand 0hm's Law for more generality by saying: V= I*Z, or Z = V/I.
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* Because impedance is a complex number, there are actually several "types" of power (true, reactive, and appearant). In a DC circuit, we can stick to true power by saying: P = V*I -or- P = I²R -or- P = V²/R. All three are equivalent because of the V=I*R rule.
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* Charge (Q) is a measure of how many electrons occupy some finite space. Because charge is important while dealing with capacitors, we can say:
Capacitor Charge (Q) = Capacitor Voltage (V) * Capacitance (C)
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* Capacitance and Inductance are where Calculus comes into play. The capacitor voltage and current is always:
Vcapacitor = 1/C ∫ i(t) dt + Vinitial (integral limits: 0 to t)
Icapacitor = C * (di/dt)
No, i = C dv/dt
The actual capacitance of a capacitor is set by the plate area, the plate spacing, and the dielectric material.
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* Inductors have a similar pattern:
Vinductor = 1/L ∫ v(t) dt + Iinitial (integral limits: 0 to t)
Iinductor = L * (dv/dt)
No, v = L di/dt
The actual inductance of an inductor is set by the number of turns, the radius of the coil, the core material, and the inductor length.
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* Transistor Current Gain is signified by β and α. (β is sometimes called "Hfe"). Beta is the ratio of collector current to base current. Alpha is the ratio of collector current to emitter current. So to sum it up: Beta = Ic/Ib. And Alpha = Ic/Ie. Also, the two are inter-related by:
α = β / (β + 1)
β = α / (1 - α) <--- Double-check me on this one
...it's important to note that β and α
only describes the transistor and not the whole amplifier. Also, the two are not constant, and β tends to shrink and as the transistor saturates and begins carrying its maximum current.