# resistor voltage drop

#### willdr

Joined Aug 14, 2008
2
how is the voltage drop across a single resistor calculated? In a simple E Mosfet circuit from where are the measurements for Vg and Vd taken?

#### SgtWookie

Joined Jul 17, 2007
22,210
how is the voltage drop across a single resistor calculated?
Ohm's Law:
E = sqrt(PR), or Voltage = the square root of (Power in Watts x Resistance in Ohms)
E = P/I, or Voltage = Power in Watts/Current in Amperes
E = IR, or Voltage = Current in Amperes x Resistance in Ohms
In a simple E Mosfet circuit from where are the measurements for Vg and Vd taken?
The reference is the source. It's usually specified (respectively) as Vgs and Vds or Vdss.

#### willdr

Joined Aug 14, 2008
2
I have 15v Vdd and one resistor 2.7 Kohms gong into a E mosfet and I measure 3.544v for Vd but have not been able to calculate it.

#### SgtWookie

Joined Jul 17, 2007
22,210
I have 15v Vdd and one resistor 2.7 Kohms gong into a E mosfet and I measure 3.544v for Vd but have not been able to calculate it.
Why don't you post a schematic of your circuit?
That's much easier than trying to describe it.
As of this moment, I have no clue as to what your Vgs is, what MOSFET you're using, or even if it's N-ch or P-ch.

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