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Electrical Engineering

Rearrange formula (charging battery)

A battery is charged. The relationship between the charging current, i amperes and the time, t hours passed, is given by the formula: i = 3 e to the power of -0.36 t Show the formula for i can be rearranged to give the time t as t= 1 divided by 0.36 log e (3/i) Show all steps of working this out please!

Average current and average voltage

A full-wave bridge rectifier circuit with a 1-kohms load operates from a 120-V (rms) 60-Hz household supply through a 10-to-1 step-down transformer having a single secondary winding. It uses four diodes, each of which can be modeled to have a 0.7-V drop for any current. What is the fraction of a cycle that each diode conducts? W

Signal Processing

See attachment for better symbol representation. 1. Find and sketch the spectrum of the following signal. x(t) = cos(t) + cos (2t)*cos(3t) (Express the trigonometric functions in terms of complex exponentials using one of Euler's formulae, then perform the arithmetic (multiplication) and then express x(t) in terms of sep

Primary and Secondary Voltage

A transformer has a primary voltage of 115v and a secondary voltage of 24v. If the number of turns in the primary is 345, how many turns are in the secondary? (a) 8 (b) 72 (c) 690 or (d) 1,653 ?

Finding total resistance of two devices

A circuit contains two devices that are connected in parallel. If the resistances of one of these devices is 12ohms and the resistance of the other device is 4ohms, the total resistance of the two devices is? (a) 0.0625 (b) 0.333 ohms (c) 3 ohms (D) 16 ohms

Finite State Machine

Finite State Machine A finite state machine (FSM) is either deterministic or non-deterministic. A deterministic FSM (DFSM) is a FSM with at most one transition for each symbol and state. A non-deterministic FSM (NDFSM) is a FSM whose transition function maps input symbols and states to a (possibly empty) set of next states. T

'Digital Filtering'- MATCAD problem

Plot the frequency response and the poles and zeroes in each case. Use a sampling frequency of one rad/sec. Compare the filter frequency responses. (See attachment for full question).

Transmission Delay

A two-port bridge connects on the end of a cable of length X m. to the end of a similar cable of length 3x/2 m. Hosts are attached at various points on the cable system, which operates as a shared-access LAN implementing the CSMA/CD protocol with a minimum frame length of 512 bits. The bridge imparts a delay in forwarding frame

IP address routing

Suppose a router has built up the routing table shown in Table below. The router can deliver packets directly over interfaces 0 and 1, or it can forward packets to routers R2, R3, or R4. Describe what the router does with a packet addressed to each of the following destinations (see Attachment)

Calculate the delay angle (alpha)

The three-phase half-wave converter in figure below is operated from a three-phase wye-connected 220V, 60 Hz supply and the load resistance is R=10 ohms. If the average output voltage is 25% of the maximum possible average output voltage, calculate the delay angle (alpha). See Attached File.

Determine the peak-to-peak ripple current

An Rl load as shown in figure below is controlled by a chopper. If load resistance R=0.25 ohms, inductance L=20 mH, supply voltage Vs=600V, battery voltage E=150V, and chopping frequency F=250 Hz, determine the peak-to-peak ripple current (delta I). See Attached File.

RMS current ratings of a diode

The waveforms of the current flowing through a diode are shown in the figure below. Determine the RMS current ratings of the diode.

Bode Plots

Sketch the Bode magnitude plots for the following functions: (a) T(s)=-10s/(s+20)(s+2000) (b) T(s)=10(s+10)/(s+1000) Bode plots were introduced in my second circuit analysis class, but I really didn't think it was important because it looked like an outdated tool no longer in use. Other than changing s to jw and plottin

Derive the expression for the small-signal voltage gain.

The common-emitter circuit has an emitter bypass capacitor. (a) Derive the expression for the small-signal voltage gain Av(s)=Vo(s)/Vi(s). Write the expression in a form similar to that of equation (Av=(-Gm*Rpi*Rc)(Rs+rpi+(1+Beta)Re)*((1+s*taua)/(1+s*taub)). (b) What are the expressions for taua and taub? The circuit is

Basics problems of Induction motor

The frequency of the induced rotor currents in the rotor of a 60 Hz induction machine is 2 Hz. Furthermore, the fields in the air gap turn at -40 rpm with respect to the rotor. (a) Find the number of poles. (b) Find the slip of the motor. (c) Find the synchronous speed in rpm. (d) Find the motor speed in rpm. (e) Is this a

Diode DC Models: calculating current and diode parameters

1) Two identical diodes are connected in series with 100 ohms and a 2 V battery such that each diode is forward biased. Let Io = 10fA; n = 1, T = 25 degrees C. Calculate the loop current if (a) ideal diodes are assumed; (b) VD = 0.6 V for each diode; (c) each diode is represented by a piecewise-linear model that is exact at ID

Verifying Voltage Measurement

The circuit shown in the attached figure was built in the laboratory and V0 was measured to be 6.25V. Verify this measurement using the voltage divider principle, whether measured result is consistent with the figure.

Current through the inductor

A security alarm for an office building door is modeled by the circuit as shown in the attachment. The switch represents the door interlock, and V is the alarm indicator voltage. Find the current through the inductor, iL(t), for t>0. The switch has been closed for a long time at t=0.