# Numerical - Gate-to-source voltage

Q.  What is the value of gate-to-source voltage (VGS) for the circuit diagram shown below?
- Published on 24 Sep 15 a. 1.5 V
b. 2.9 V
c. 3.5 V
d. 4.9 V

#### Discussion

• suranjan mallick   -Posted on 09 Jul 17
good.
• Satyawati   -Posted on 05 Oct 15
Given data: VDD = 5V
Drain current (ID) = 0.3 mA
Source resistance (Rs) = 7kΩ

To determine:Gate-to-source voltage (VGS) for the given circuit diagram

Formula: From the given circuit diagram, by applying KVL to drain- source loop,
VDD = VDS + ID RS

Method of computation:
From the given circuit diagram, by applying KVL to drain- source loop,

VDD = VDS + ID RS ---------(1)
But, VDS = VGS

Therefore, by replacing VDS by VGS, we can write,

VDD = VGS + ID RS -----------(2)

By re-arranging the terms, we can write,

VGS = VDD - ID RS ----------(3)

Now, substituting the given values of VDD , ID & RS in the equation (3),

VGS = VDD - ID RS
= 5 – [(0.3 x 10-3) x (7 x 103)]
= 5 – 2.1
= 2.9 V

Therefore, the gate-to-source voltage (VGS) for the given circuit is estimated to be 2.9 V

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