Understand this simple circuit

[angy]

I was troubleshooting a circuit and i came to this part of circuit .it contains zener diode(3.3V) and a pull down resistor.When i apply supply voltage(10V) i should get 6.7 V.But during troubleshooting i found full 10V across output .later i found resistor was not properly grounded .Now my doubt is when one end of resistor is not grounded how do we get 10V across output.

 

[kam1787]

I think your reading was because of leakage current

 

[pha0001m]

Now my doubt is when one end of resistor is not grounded how do we get 10V across output.

If your resistor is not grounded, that mean you have an open circuit, thus no current flow. Therefore you will see the entire full ten voltage at the output.

If that is confusing, just imagine the open circuit as an infinitely large resistor. Now apply the basic voltage divider rule, of course the entire 10V will drop across this infinitely large resistor.

 

[crutschow]

If the voltmeter has a typical high resistance than the current through the Zener diode is very small.
This current is likely less than the diode leakage current so basically the full voltage appears across the voltmeter.