Electrica

Question 1

Electric charge can be distributed from one place to another under the influence of an electric field but the algebraic sum of positive and negative charges in the system cannot change

Answer 1

Conservation of charge

Question 2

The total electric flux generated by a point charge is proportional to the charge. Formula

Answer 2

electric flux = Q/ε

Question 3

Que determina el flux que pasa a traves de un medium?

Answer 3

Permittivity of a medium , ε

Question 4

Columbus Law formula

Answer 4

F2 = Q_1Q_2/(4piεr^2) a_r12

Question 5

___ Law states that the total electric flux passing out of an enclosing surface is proportional tot the total charge withing the surface.

Answer 5

Gauss’ Law

Question 6

(T/F) The mathematical formulation of Gauss law states that the total enclosed charge can be determined by summing all of the electric fields on the Gaussian surface.

Answer 6

True

Question 7

Formula - Work performed by a moving charge Q1 from point 1 to point 2

Answer 7

W = - Q* integral (E*dl)

Question 8

Formula - Work performed in moving a point charge QB in the radial direction withing a field crated by point charge QA

Answer 8

W = - integral (F * dr) = - integral (Q_A&Q_B/(4piεr^2) =
(Q_A * Q_B/4piε)* (1/r_2 - 1/r_1)

Question 9

Formula - Work done in moving an object of charge Q a distance l parallel to a uniform field

Answer 9

W = - F* l = -EQl = -V_plates Ql/d = -Q* delta V

Question 10

___ Law states that an induced voltage, v, will be generated in a circuit when there is a change in the magnetic flux.

Answer 10

Faraday’s Law of induction

Question 11

Propiedad del circuito para oponerse al flujo de corriente

Answer 11

Resistance

Question 12

Resistors in serie

Answer 12

Rs = R1 + R2 + R3

Question 13

Resistors in parallel

Answer 13

Rp = 1/(1/R1 + 1/R2 + 1/R3)

Question 14

(T/F) Resistors in serie comparte la misma corriente

Answer 14

True

Question 15

(T/F) Resistors in parallel comparten el mismo voltaje drop

Answer 15

True

Question 16

Capacitors in serie

Answer 16

1/Cs = 1/C1 + 1/C2

Question 17

Capacitors in parallel

Answer 17

Cp = C1 + C2 + C3

Question 18

Inductores en paralelo

Answer 18

1/Lp = 1/L1 + 1/L2

Question 19

Inductores en serie

Answer 19

Ls = L1 + L2 + L3

Question 20

Resolver circuitos con Ley de Ohm, pasos para hallar los I, delta V por cada resistor

Answer 20

1. Simplificar el circuito lo mas posible hasta dejarlo en 1 solo resistor
2. Calcular la corriente ya que el Voltaje antes del resistor sera el de la bateria y el voltaje luego del resistor sera 0.
3. Ir expandiendo al circuito mas complejo. Por ejemplo, si antes del mas simple habia un circuito con 3 resistores en serie - se sabe que la corriente no cambia en los resistores en serie, por lo tanto se puede calcular el voltaje drop en el resistor. Pero el voltaje real del nodo sera la resta del V antes del resistor menos el V drop durante el resistor.
4. Seguir expandiendose al circuito mas complicada, por ejemplo si ahora lo que continua son resistores en paralelo, se sabe que el V no cambia entre ellos solo la corriente. por lo tanto se calcula el V drop con los valores que ya tenemos de V y se calcula la corriente por cada resistor

Question 21

Resolver circuitos con Ley de Kirchhoff’s

Answer 21

1. Establecer las corrientes por cada branch del circuito. Le dimos direcciones que no es necesario estar correcto en ellas.
2. Creamos la ecuacion de corrientes en uno de los junctions que las una todas
3. Se crean Loops
   - En estos loops si la corriente va desde el lado - al + de la bateria entonces hay un rise en voltaje y es (+) la ecuacion
   - Si pasamos un resistor y la corriente va en la misma direccion que nos estamos moviento entonces hay un voltaje drop y es negativo
   - Todo se iguala a 0.
4. Se crean los loops necesarios para encontrar la cantidad de variables desconocidas.

Question 22

Amplificator factor formula

Answer 22

Av = V_out/V_in
Ai = Beta = i_out/i_in

Question 23

Que son los amplificadores

Answer 23

Pueden aumentar o disminuir la senal, cambiar de signo o de phase.

Question 24

Ideal voltage amplifier has an infinite ____ impedence and zero ___ impedance

Answer 24

1. input / v_in appears across the amplifier and no current or power is drawn from the source
2. output / all of the output current flows thorugh the load resistor.

Question 25

Class ____ amplifier has a quiescent point in the center of the active region of the operationg curve. Greatest Linearity and least distortion. Load current flows throughout the full input signal cycle. Efficiency 50%

Answer 25

Class A

Question 26

Class __ amplifiers has the quiescent point established at the cutoff point. A load current flows only if the signal drives the amplifier into its active region, and the circuit acts like an amplifying half-wave rectifier. In pairs/transistors/push-pull operation. Efficiency 78%

Answer 26

Class B

Question 27

Class __ amplifier has a quiescent point somewhat above cutoff but where a portion of the input signal still produces no load current. The outpout current flows dor more than half of the input cycle. Each output transistors conducts for slightliy less than 180 degrees of the cycle.

Answer 27

Class AB

Question 28

Class ___ amplifier have a quiescent points wll into the cutoff region. Load curent flows during less than one-half of the input cycle. Efficiency 100%

Answer 28

Class C

Question 29

Para resolver KCL con nodos se tiene que igualar las I de entradas al nodo = con las I de salidas al nodo

Answer 29

Cierto

Question 30

Op Amp - The outpout voltage should remain withing 3V from either value to avoid distortion of the output signal at rated values.

Answer 30

|v1 - v2| < (V_dc - 3V) / A

Question 31

Ideal Operational Amplifier Characteristics / Rules

Answer 31

1. Zin = infinite 2. Zout = 0 3. A = infinite 4. BW = 0 5. Vout = 0 when v+ =v- 6. Current to each input is zero 7. Voltage between the two inputs terminals is zero 8. op amp operates in the linear range n

Question 32

If a potential difference is generated by a single conductor passing through a magnetic field the potential difference depends on-

Answer 32

-Speed with which the conductor cuts the magnetic field - Lenght of the conductor - Magnetic field density - No depende del diametro del conductor!

Question 33

Como saber si los resistores estan paralell or series

Answer 33

Paralelo - tienen junction y dos cables con los que comparten voltajes diferentes (comparten los voltajes de los cables) Serie - Es el mismo voltaje atraves de todo el loop

Question 34

Which measurements are required to determine the phase angle of a single-phase circuit

Answer 34

Power, Voltage and Current

Question 35

AC - Power Factor relation to real power P, reactive power W and complex power S

Answer 35

pf = P/S

Question 36

Un circuito con un pf =1 quiere decir que es resonant, entonces f=60Hz

Answer 36

True

Question 37

Para calcular Vout con amplificadores

Answer 37

Se utiliza KCL en nodos. La suma de los I que entran igual a los I que salen Si el I entra en el nodo la resta de los voltages es el voltaje de afuera menos el voltaje del nodo. Si el I sale del nodo la resta es el voltaje del nodo menos el voltaje de afuera.