electronic circuit calculation

[johnson pay]

Who can help me to calcurate the Vin ,and write down the step for me ,thanks:-o

 

[godfreyl]

@ johnson: It's got "4V" written next to the input, so the input is probably 4V.

@ everyone else: Warning: that picture's a 2MB download and the scribbling on the right is illegible even at full resolution.

 

[Dan Mills]

To find the open circuit voltage, work the problem like this:

Open circuit, so the current in the 6 ohm resistor is zero, therefore the voltage drop across this resistor is zero
=> Open circuit voltage = voltage across the 2 ohm resistor.

Current around the loop V/R is 10V/(2 + 3 ohms) = 2A.

Voltage across 2 ohms with 2 amps flowing = IR = 2 Amps * 2 Ohms = 4V.

Regards, Dan.

 

[johnson pay]

The answer is 4v,vin is open circuit so the 6R is ignore ,open circuit current=0,voltage=0.
Thanks for your help godfreyl and Dan Mills.


Regards, Johnson.