Question

Problem #5 Ri Vy= Probe I R- 1502 o VOLTMETER INPUT CIRCUIT Probe 2 Express resistance in ohms (2) and voltage in volts (V) Requirements-Part 1 (voltmeter not attached yet) a) Suppose you want to produce a voltage of 1 V across resistor R2 (i.e. Vor 1 V) Use the voltage divider equation to find the value of Ri that is needed to do this. b) Using your design value for Ri, verify that the voltage drop across Re is, indeed, 1 V. Requirements-Part 2 (voltmeter attached to voltage divider) Suppose you have a voltmeter, which is a device that measures voltages. Probe 1 is connected to node b, and Probe 2 is connected resistor of value Rin, which is effectively in parallel with Ro during the measurement. to node c. The input resistance of the voltmeter is modeled by a Note: All real-world voltmeters have a built-in resistance at its input terminals due to the internal circuitry of the voltmeter. It is unavoidable. c) Derive a general equation for Vos that includes the effect of R d) Write a MATLAB program that plots the output voltage Vour versus R. . Make plots with linear axes for these Rin scenarios: i) i Ω to 1000 Ω, and 2) 1 Ω to 1 M2 (mega-ohm) In both cases, use the logspace function to create an Rn vector with 100 data points. Use your equation from Part (c) to create a Vase vector from the Ram vector. Use subplot to put the plots side-by-side. Provide proper axes labels and titles. Attach a copy of your plot to your paper solutions. e) Using the results from Part (e) and (d), what is your conclusion about how the input resistance of the voltmeter affects the measurement of Vou? What would be the ideal input resistance to achieve the most accurate voltage reading? Explain. Upload your MATLAB code (named hw_a1p5m) to the Hwal D2L Submission Folder. 1,542
can you sovle this problem, also I need the code for part d. thanks

Answer 1

Part 1

(a)

From voltage divider equation;

$V_{out}=V_s[R_2/R_1+R_2]$

31

out 11

Ro 1500

1-3150/R1 + 150

+ 150 = 450

$R_1=300\Omega$

(b)

Current

1R2 = 0.0066 * 150 1 V t

Part 2

(c)

$V_{out}=V_s[R_2'/R_1+R_2']$

where, $R_2'=R_2||R_{in}=R_2.R_{in}/(R_2+R_{in})$

(d)

Matlab code:

R1=300;
R2=150;
Vs=3;
subplot(1,2,1); %Subplot to plot side by side
Rin=logspace(0,3,100); %logspace function to create Rin with 100 data points
for i=1:1:100
Vout(i)=Vs*((R2*Rin(i)/(R2+Rin(i)))/(R1+(R2*Rin(i)/(R2+Rin(i))))); % finding Vout
end
plot(Rin,Vout); %Plotting Vout vs Rin
subplot(1,2,2);
Rin=logspace(0,6,100);
for i=1:1:100
Vout(i)=Vs*((R2*Rin(i)/(R2+Rin(i)))/(R1+(R2*Rin(i)/(R2+Rin(i))))); % finding Vout
end
plot(Rin,Vout);
axis([0 100000 0 1.2])

0.9 0.8 2 0.8 0.6 0.6 0.5 0.4 0.4 0.2 0.1 0 500 1000 10 5 0

(e)

As the input resistance of the voltmeter tends to infinity the Output Voltage tends to true value or error tends to zero. Ideal input resistance of the voltmeter should be infinity to achieve most accurate voltage

From (c)

$R_2'=R_2||R_{in}=R_2/(R_2/R_{in}+1)$

When

R,n= infinity:R,= R2