compund voltage dividing calculator or equation help

[mdmcs1]

hey all!

i have this circuit (see attached) and i am wondering if anyone has run into an online calculator that would solve this for me, or if you could post the equation that i need to solve this problem. I would like to know what my voltages should be at points X, and Y on the attached pdf.

thanks to all of you for your help!!!

michael

 

[Ross Craney]

X = 0.95V & Y will be the same under no load conditions. With a load everything will change depending on what the load is.

 

[Jaguarjoe]

Read chapters 6 and 7:

 

[mdmcs1]

i will read those chapters again right away,

but - (and i forgot to include this in the original post) the volts i measure at X, and Y of this circuit using a scope is right about 1.4v - thus the need to ask the original question.

 

[crutschow]

The best calculator (simulator) for that is the free program LTSpice.

Otherwise, since there is no load, the left 10k resistor has no effect on the voltage since there is no current flowing through it, so Vx = Vy

Next calculate the parallel value of the right two resistors: (33k x 10k)/(33k + 10k) = Rp.

Finally calculate the voltage division between that parallel resistance and the top left 33k resistor: 5V x Rp / (Rp + 33k) = No-load output.

 

[MikeMl]

And if this is homework, you know what you should have done...

 

[crutschow]

(and i forgot to include this in the original post) the volts i measure at X, and Y of this circuit using a scope is right about 1.4v - thus the need to ask the original question.

The scope is not No-load. It adds a load equal to its input resistance (typically 1M ohm direct or 10M ohm with a 10:1 probe). But either of those is small compared to 10k ohm, so its effect here is minimal.

 

[mdmcs1]

exactly what i was thinking Carl, the scope shouldnt change it this much - but yet i am reading 1.4v and havent found the reason for it - i have replace all 4 resistors with known correct ones (i ohm tested each of them) and set this up again - and i get the same thing.... darn 1.4v!!

 

[crutschow]

The voltage should be about 0.94V (see simulation below). Suggest you double-check your circuit layout.