I am trying to analyze a circuit using source transformations (converting from a voltage source to a current source). I am trying to understand how they work based on a book, but I keep getting confused based on a simple example.

The book says that it is obvious that V0 is the negative of the ratio of the "feedback" resistor (8k ohms) to the input resistor (2k ohms) multiplied by the voltage the input terminal, thus it is -8 volts.

It may be that my brain is currently fired, but the ratio of the resistors part through me for a loop.

dear sirs
i want to connect 20 leds in parallel.
my source is 2x 4.2v batteries parallel
led voltage white 3.4v 20ma
in the following page i can find that i need 20 resistors 47ohms
http://led.linear1.org/led.wiz

now in other page
http://www.hebeiltd.com.cn/?p=zz.led...tor.calculator
i find out that i need resistor 2ohms 03w
does it mean that i need 1 resistor for all circuit?

Why is the resistor placed one on top of other...instead of using a separate voltage divider from the battery to compare the voltage....this resistor one on top of other just makes it look more complex and complex for calculation too....
Attachment 70991
Is there a special reason....a hidden trick in this circuit....I don't see the meaning of just complicating(besides saving...3 resistors)....

HI. I want to know how to choose suitable resistors(value) around transistor.
this contents is from Electronics all in one for Dummies.
Please refer the attached file, and answer the question.

Contents in Book
- R1: 330ohm resistor limits the current through the LED to prevent the LED burning out. You can use Ohm's law to calculate the amount of current that the resistor will allow to flow.

Given the circuit shown in the attached picture, of a constant current source (i) with a series switch to a load consisting of a resistor (P) in parallel to a capacitor (C) and resistor (S) in series. Assuming the voltage across the capacitor is initially 0; what is the equation describing the voltage across the resistor P with respect to time, assuming the switch is closed at time=0?

I need to mesure 400V dc from MCU with reference voltage of 5V.

So only way I see is to use voltage divider & use factor of 80.

that is 790K & 10K resistor with it.
This will make 5V when 400V is applied.

1. Is my calculations are correct.
2. Is there any method to do with it.
3.

I need a help. Can anyone help to find out the voltage drop across the 1.5R parallel resistor and effect of the rectifying diode on the circuit?

Here in the circuit image CT1 and CT2 are the current transformer leads of 1000:1 CT, that if there is 1000A in primary 1A in secondary.

My problem the CT current is bridge rectified using 1 schottky diode and one tvs diode as shown in image.

Hi,
i need urgent help if you can help me. I am working on a project for which i am trying to built a circuit that will automatically compensate for impedance mismatch between two resistors by varying the current provided to each resistor so that the voltage across both different resistors will be the same. I have attached the circuit design.