[SOLVED] How to find the Zth of this circuit?

[darrenbkl]

impedance

Hi , for this question, can anybody teach how to find the Zth of this circuit?
because of the L1, i dunno how to solve that,thx.
**broken link removed****broken link removed**

 

[Bhanumurthy]

Re: impedance

Hey,
Itz a bit vague...Can u be more clearer?

 

[darrenbkl]

impedance

emm,I mean i want to find the thevenin equivalent impedance looking from the right side, can anybody solve tat for me?with complete working,thx very much

 

[saruman1983]

Re: impedance

Zth=R4//R3//(1/jwC2)//(R1+R2//jwL1)

Added after 40 seconds:

w=60Hz

 

[graciousparul]

Re: impedance

Please make the circuit diagram clear

 

[JoKKeR]

impedance

You can use simulator ... For example multisim or proteus. Multisim is simpler.

If ur interested in calculation, you need to get formulas and equations. You may need a material to learn from.

Material:
http://www.ene.ttu.ee/leonardo/elektro_alused/

Itis in estonian but im pretty sure that if you want you will find what you are looking for..

 

[laktronics]

Re: impedance

Hi,

Whatever Saruman has written except ω=2Πf and not 60Hz.

Regards,
Laktronics

 

[saruman1983]

Re: impedance

Yeap. That's a classic mistake i always do. I keep omitting 2π when calculating impedance components (It has often led me to very wrong results, obviously).

 

[darrenbkl]

Re: impedance (help me solve some problem) !!

I always confuse of the component that hang across the sky there,in this case is L1. so basically we paralled the component inside then only deal with outside right?

Added after 3 hours 17 minutes:

How about this two question,i know it is simple but i still cant figure it out.

1)Using Thevenin's Theorem,find the voltage across R4.


2)Simplify the circuit external to R3 to its Thevenin Equivalent.

 

[saruman1983]

Re: impedance

1)You must replace all of the circuit except the resistor R4 witn its thevenin equivalent, then the apply a voltage divider equation between R4 and the Zth of the rest circuit.

In this case,(with the voltage source short circuited) the Zth of the circuit neglecting R4 is:

Zth=R3//-jXC//(R1+jXL//R2)

In order to find the Vth one must open circuit the circuit left of R4 and calculate the voltage at the floating node as (Vs in normal operation):

Vth=Vs*(R3//(R1+jXL//R2))/(R3//(R1+jXL//R2)-jXC) (voltage divider too)

The voltage acrooss R4 is:

V4=Vth*R4/(R4+Zth)

Added after 10 minutes:

2)Again, short circuit Vs, then calculate the impedance seen from a,b as:

Zth=-jXC//(R2+jXL//R1)

As before, open circuit a,b (i.e. remove R3) and calculate the voltage Vab with Vs in normal operation (might need a little bit of calculations)

 

[darrenbkl]

impedance

thx saruman for ur patient : )
about the bridge circuit,is there any rule associate with it?

 

[saruman1983]

Re: impedance

It would be pretty easy since with the removal of R3 there is no bridge at all from what concerns the thevenin equivalent. You can use 2-3 voltage divider equations to find Vth, finding VXL and VR2 and then adding them. In any case, if you are interested in calculating impedances of circuits containing bridge components, i think it would not be difficult either to find some examples or general relationships on google or wikipedia (i can't remember the relations right now).

Cheers,
vag

 

[darrenbkl]

impedance

can anyone explain me how capacitor smooth out rectified voltage? I don't understand,in detail,how does the caps respond to the rectified dc voltage.

Does the smoothing cap must be electrolytic cap?