I know the final answers are V TH = 248.7761 nV , R eq = 15 Ohms , T eq = 298.98
ID: 2267217 • Letter: I
Question
I know the final answers are VTH = 248.7761 nV , Req = 15 Ohms , Teq = 298.9833 degree Kelvin. Show me the steps to get those answers.
Consider the configuration of noisy resistors shown in Figure P5. Each resistor operates at a specified temperature as noted in the figure. Assume that the measurement bandwidth, B, is 250 kHz. Perform the following: (a) Calculate and sketch the Thevenin equivalent circuit of the noisy resistors. Indicate the Thevenin voltage source and equivalent resistor together with its equivalent operating temperature. (b) Accurately sketch and label the two-sided mean-square open-circuit voltage spectral density function. Components: R = 10 N, 68°F R2 = 10 Q, 59°F R3 = 10 N, 86°F Figure P5: Noisy Resistors SOLUTION SUMMARY (a) VTH = , V- in polar form, (b) Req = (c) Teq = , °K CALCULATIONS (Show all calculations to receive full credit)Explanation / Answer
Ans : Part (a). The Thevenin equivalent circuit of a noisy resistor is as shown below.
It consists of a noise source with a voltage defined by Equation
V2rms =4KTBRV2 , where K = Boltzman's constant = 1.38x10-23 w-s/.K
Here, B = 250KHz is given
so, Thevenin eqiuvalent voltage is calculated by putting all values in above equation.
and a noiseless resistor with a value of
RL = (R1||R2)+R3 = 15 OHM